That’s absolutely ridiculous. Although there’s no way to determine why they do the things they do, what’s your best guess? For example: Do you use CoinJoins, or deposit small amounts (that set off a red flag with kraken on my account one time)? Are you using some unusual offshore bank to fund the account?
Not that any of that stuff should make a difference. These guys are complete jerks for doing this to you. I’m just curious to know what YOU think happened, if you had to guess.