Don't forget to take screenshots of your gambling history, total balance, and interactions with their services, it will be useful as proof if they don't give you your money.
But it usually takes quite a long time, there are even cases of withdrawals for more than 6 months in maintenance, you have to be really patient with that.

But wait a minute, did they give you a notification, how long will they finish with the maintenance period? If you get the notification it's much better because you know how long you will have to wait for the maintenance to finish.

So you are doing KYC and while you are waiting for the process, you keep playing till you lose half of your balance? That's a big mistake imo, you should stop while the KYC is in the process but of course it is your money and you have full right to do anything with it. It is just unfortunate if you lose what you have won while you are doing KYC which means that you are willing to withdraw it but you did not patient enough to wait. Hopefully you still have some balance left now and when the KYC is verified, you can withdraw your remaining balance.