Hey buddy, First, sorry for the inconvenience that this might have put you through. Second, I must say you made the mistake of receiving a payment that's not coming from your own address directly into an exchange account. Tinted coins are real, and they are being taken seriously. We don't like it, but they have been put in place by some regulators just as an excuse to confiscate users funds for any reason they can tag to it.
 
Due to the high rate of tinted addresses and all of that, it was a very bad idea to receive the coin with a centralised exchange, especially for an amount that is above $1,000. Any exchange that is licenced and operates under any legal body always has some algorithm that helps them detect addresses that have tinted funds on them, which could be what you are facing right now.
 
Lucky for you, the exchange in question has an ANN thread here on this forum, but the bad news is the thread has been inactive for a very long time now, which means their representative hasn't come here to update it, and the representative account has not been active since last year either.
Fixedfloat ANN thread 1: https://bitcointalk.org/index.php?topic=5103574.0
Fixedfloat ANN thread 2: https://bitcointalk.org/index.php?topic=5119443.0
Representative profile: https://bitcointalk.org/index.php?action=profile;u=2387384
 
If the email attached to the representative's account is active, sending them a personal message here on this forum referencing this thread might call to their attention if they get the mail. There is no harm in trying, but it may lead to a dead end.