Locked accounts usually don't get any replies. I honestly don't think you can get $1200 back. Of course, you have to try your luck to the fullest. Hope you can get your money back.
Depends on the site. If it's those unpopular websites, expect that there will be no fair judgment on the case. Those sites will not give $1,200 in just a simple KYC as a solution. If it's involved legit and popular websites, as long as everything turned good on their investigation, the chances of getting that amount are high.
OP never mentioned the name of the site. Only if we know it, we might contribute to pressuring the site if we see it's unfair.
^ It seems a loophole to the unpopular gambling casino, if you violated the rules they have a reason to lock your account and forfeited your balance without knowing you and you did not receive even any single response. However, it is opposite to the reputable gambling casino, probably KYC is a part to boost their users for legalities which are following government protocol by having a full KYC procedure.
Nevertheless, for the large amount, this will always be expecting that there is KYC, that is why I prefer to read first the TOS before using any gambling platform casino which gives you a knowledge towards their TOS.