@OP - If you manage to get your funds out never ever use these scammers again. Just remember, coinsbit, p2pb2b, whitebit and of course exrates are all operated by the same scammers.
@allyouracid - just as you stated, they are letting him have his crypto back but dragging it out by returning it in small pieces but is this really the classic case of selective scamming? It does not appear to have the hallmarks.
Good to see progress, here. Them arbitrarily allowing you to withdraw random amounts imho is a sign they're selectively scamming their users. Maybe they run on fractional reserve, and in such cases, it is sometimes enough to just be annoying. It's not that high of an amount, so chances are good that they'll give in at some point and let you withdraw your remaining amount.
Just stay friendly (as you did… I know there's plenty of reason to not stay friendly, but if you need your money back, this is sadly the best way to go), and remember them again and again, and hopefully, you will be able to get everything out of this nonsense exchange.