What I understand is that they are doing this so that people can not request any withdrawal but this is very unethical business conduct. At this point I am in doubt if this is a scam attempt or buying time.
Then they should disable the deposits of that particular altcoin instead like what other exchanges do, they even announced such update. I really think that this is one of their way to take their users funds and telling that its your fault to send amount when blabla.
On the other hand, Op must have checked from their end if gate.io has a particular RBTC pair available for trading or what. Try to be in talks with them Op, don't leave the issue as it is because exchanges will not update you often about it, it is you now who should knock them once every few days to get to know when they will allow the withdrawal.