[+++UPDATE2/6+++] Gaon has just released the numbers for the month in question that will hopefully settle some of the ongoing debates and speculations, thanks to a few readers who brought it up.
As provided in the screencaps below, CNBLUE's album sales on Hanteo clock in at 75,3xx units, while on Gaon, they clock in at 95,949 units. By the formula, they are right on the Gaon > Hanteo scale and so there should be no reason for further speculation of buybacks.
There has been no Pann post on it updating netizens of the numbers (and I don't really expect there to be one since netizens never cover their tracks) but I'll look around for anything else that might clarify the matter further. I've already seen several CNBLUE articles where the top netizen comments (less than +50) were accusing them of buybacks so I suppose the damage is already done to some extent.
This is an older Pann post that tries to debunk the buyback speculations that I'll include:
"People seem to think that CNBLUE doesn't have any fans because their fancafe is a ghost town but they have a lot of adult fans who are active in other communities like the CNBLUE Gallery and Jung Yonghwa Gallery.
FNC is also busy promoting their rookies so they don't have the money to be throwing around on buybacks for CNBLUE. What would you expect from a company who drops $10 million on building a non-needed house. Do you guys even know what kind of CEO Han Sung Ho is?
Our fandom is also not weak when it comes to international fans. At their last concert, fans were surrounded by Japanese fans. A lot of Korean fans were left behind crying because they couldn't grab tickets."
Reader request. The way this was organized was too confusing to just do a direct translation of so sorry that I chose to summarize it instead.
Pann: CNBLUE's album buyback eventually revealed 
What the Pann basically states is that there are three points of suspicion with CNBLUE's recent sales that are leading to the conclusion that FNC Entertainment bought back their albums. I double checked all of this on Hanteo because there were a few wrong examples given that I'll elaborate on later.
1. Hanteo resets daily sales for all artists every day at around 10 a.m. Hanteo users and other fandoms noticed that CNBLUE started every single day off at 500 sales already made while every other artist started at the expected 0. This is impossible unless 500 fans were waiting outside record stores and buying CNBLUE's CD at the exact moment Hanteo resets.
2. Album sales normally drop over the weekend, specifically on Friday, Saturday, and Sunday. CNBLUE did not drop and also managed to sell 3,000 on each of those three days while other artists dropped and barely hit 1,000. The following week, they sold 80 albums.
3. Fans and netizens claiming that this was a buyback all decided to wait for the Gaon chart to 'test the truth', so to speak. Judging by their Hanteo sales that week, CNBLUE should have been ahead of SNSD since they tripled them in sales, but the Gaon chart showed SNSD at #1 over CNBLUE.
This raises red flags because your results on Gaon should always be greater/better than your results on Hanteo (this is where all buyback controversies start).
|I had to redo this chart because the original source copy had the wrong numbers for CNBLUE. This chart is usually used to prove the Gaon>Hanteo formula. So by the formula, CNBLUE's numbers for 2012 are normal.|
Think of Gaon as like a test. Gaon puts out a test saying you can only earn up to 100 points. Hanteo is your score on the test. You can earn 80, 90, or even a 100, but what happens when you earn 110? It's impossible, and that's what happened with CNBLUE.
FNC Entertainment allegedly bought back their albums to have the sales count on Hanteo and then returned them after the numbers were put up on Hanteo (Hanteo counts every single album that went out that day, whether or not they were later returned). Gaon only counts the total number of actual albums sold, so the buyback boost would not be reflected in their score.
|The source copy only showed the first couple numbers so the totals are rounded/estimated.|
Following the formula that your results on Gaon should be greater than your results on Hanteo, CNBLUE failed the formula because Hanteo shows them as having 26,800 copies sold and yet on Gaon, they didn't manage to beat SNSD, who only sold 10,300 copies the same week on Hanteo.
That means 16,500 copies of CNBLUE's albums are in limbo.
Fans tried to shield this saying that there were 100,000 preorders made on the album, but considering that CNBLUE only sold up to 70,000 copies their first two weeks (which also included two fan signings), that still leaves 30,000 copies in limbo.
1. [+220, -106] I knew this was happening ㅋㅋㅋㅋ They sold way too many albums compared to the actual size of their fandom ㅋㅋㅋㅋ Look at the fans trying to shield this. When every other artist started the day at 0, CNBLUE started at 500 every. single. day. TVXQ, Big Bang, and SNSD all have trouble selling over 1,000 over the weekend but how does CNBLUE manage to hit the 3,000 ceiling? And the excuse that you have many international fans buying albums doesn't make sense because that's basically saying TVXQ, SNSD, and Super Junior don't have has many international fans as CNBLUE ㅋㅋㅋㅋ
2. [+204, -91] ㅋㅋㅋ I don't even know what to say because it's just so obvious. How are fans going to explain the group selling 3,000 each day for a week and then suddenly dropping to 80 after they win #1 on Music Bank? There's no room for excuse once you're caught by Gaon. 4minute and other girl groups that got caught over this were even in the news. Don't think of shielding this when this is more obvious than what they tried to pull.
3. [+169, -86] CNBLUE fans seem to think that preorders mean actual sales but just because there were 100,000 preorders doesn't mean that many were actually sold. There could be 100,000 preorders but not one actual sale, if you see what I mean.
"As a BOICE, I can say that both CNBLUE and our fandom see no pride in winning #1 through buybacks and broadcast points."
"INFINITE, Jaejoong, and SNSD fandoms were already aware of this going on because they were tracking the numbers right with them."
"The fact that they were at a 500 lead at reset is suspicious enough."
"Don't hate on CNBLUE, hate their company. I saw them start at 500 every morning, and unless they have some crazy fan buying 500 copies of one album every day, they need to come out and show their receipts right now."
"Considering that CNBLUE's song is better than SNSD's, I really can't hate on them for buying back their albums."
"Even if they won through buybacks, this #1 makes more sense than that stupid SM song winning #1."
"It sucks that F.T. Island has to sell their own albums through their skills while CNBLUE gets the full support of their company, fu*k.."
"CNBLUE has no fault in this, they're completely at the mercy of their company. What kind of a group would want to buy back an album that they composed themselves? Obviously the higher ups weren't satisfied with their progress and started getting greedy."
"FNC seems to have more money than they're letting on. Juniel's song was played on Gentleman's Class all the time."
"It's 100% a buyback because once you break the Gaon>Hanteo formula, you really have no way of explaining the difference. B2ST was in the same boat last year. Fans denied that the company was buying back albums but once the Gaon and Hanteo chart comparisons came out, they all had to shut up."
"I don't get why fans are saying CNBLUE has more Japanese fans than Korean. If that's the case, then SNSD has more Japanese, American, Chinese, Thai, etc fans all over the world and yet CNBLUE sold more than them?"