If you have read their T&C before you create your account, you should not be confused about this. Since you said that by creating another account you have been playing on their platform for several years without any problem. But now they want your ID for another account verification, to process the withdrawal.

So you have to understand here that since there was no problem in the previous account, then why is there a problem now? This means they have doubts about your activities or your fund so they want your ID. I think if you give them the right information they will process your withdrawal without any hassle.