ALWAYS read the terms of service and conditions for withdrawals. Don't fall for those scummy tactics casinos use, and its honestly quite common amongst the newbie ones too. It's really blatant and obvious that they are doing this to milk unsuspecting people of their money. The fact that its 5x the amount deposited too is nigh impossible to achieve as well.

OP, you either play it safe, leave the funds there and hope they lift this restriction up as the casino itself grows. I'm saying this because this is extremely unsustainable, as it hurts their reputation in the long run, and any gambler worth their salt would sniff their intentions through this. The other way out, if you really need those funds, is unfortunately through gambling your way out. Good luck.