I would open a ticket. In case there is a real issue requiring their specific involvement in your case, you will want to get in the queue (currently 28 days predicted wait period)
If they resolve the issue before then, and your deposit shows up. Please close your support ticket.
Creating a ticket for failed XEM deposits will also show how important NEM is to the community, and exemplify our demand for smooth XEM deposits.
Im hearing that Cryptopia are telling some of their users that support tickets are currently taking 45 days to resolve!
It's outrageous. It seems to me that this greatly spoils the reputation of the exchange. People lose confidence in such exchanges. I hope that the exchange will solve your problem.