When I talked to the forex broker about this they insisted money be withdrawn to the wallet used to make the initial deposit. I can't have been the only one who experienced this so they must have some sort of policy in place for extreme cases.
I'm not used to forex brokers or know how they operate but if you read their faq or terms and conditions they would have stated that they can only withdrawaw crypto-related transactions to the deposited address and it is their only way of preventing their customer funds from online theft.
I will advise you always read about every platform's rules and conditions before using it to avoid this kind of issue in the future.