So do you think its fair for their costumer to be ask such huge amount for recovering their funds? if its ok to you then you are tolerating a corruption happening if that one is a legitimate support of that exchange
That's an extra work for them & out of their contract. I wouldn’t even surprise if they would deny tk deposit the amount; however, they must leave the fund as it is for always.
Exchanges usually don't support a chain & that's for a reason of course. They have contract with you to pay only if you follow the rules and their terms.
Doing such work is extra burden for them. From ethical practice point of view, they should recover you fund but they are not forced to do so.