Regardless of the reason your account was restricted, the only way to get out of this restriction zone is by contacting bet365's customer support. Even if you have no idea why your account has been restricted, you should still contact customer support to get an idea so you can open it back.

You can request a withdrawal via the Account Menu ; select Bank then Withdraw. Where we are unable to withdraw back to your Debit Card, funds will be returned to you via Wire Transfer to the name registered on your bet365 account.