If there are any restrictions on withdrawal in the terms of use, then you cannot do anything because you have agreed to the conditions, but if there is no condition such as you need to make three bets before withdrawing, then you can contact the support team to find out the reason for such restrictions.
He already contacted them, they told him that he has to wager x3 in order to be able to withdraw his money which is a pretty standrad thing in online casinos. He claims that he did that as well but now his withdrawal is still pending.
It's a strange request to be forced to use the service for an account.
I am not sure I understand what you wanted to say with this. Who forced him to "to use the service for an account" and what does that even mean?