Sorry to hear you made miss transaction. When you registered your account and saw the evil ban message, there was a note that any larger amount sent to the address will not be refunded. I think that's the forum refund policy, a larger amount than the required amount will not return in scop of buy copper membership as well. But once again, the admin has the right to refund if he thinks it should refund. Only the admin could comment on that. That's the reason why we need to double-check the address during sending cryptocurrency.
Yes, that's a catch here as it is clearly written that you can pay more to cover the fee or the amount can be greater than the minimum required and the excess amount will not be returned.
Let's see how the admins respond to this but keep in mind, even if they want to refund you, it may take a few days as admins are usually busy.