That's their problem, you don't know if they are a scammer or if they are bums, some problems were solved there, the transfer of nano, for obvious reasons, was always automatic. But I think it's better to call it a coup because they had to fix it.
The reason why I mention those accusations is you must do your own research before using any exchange, if you have googled about Mercatox reputation before using the service, you wouldn't face this kind issue.
Not good, actually it's similar with this thread. It's mean actually you should move this thread to scam accusations rather than open a new thread that contain a similar discussion. This forum has a rule to not post a duplicate thread since it's considered as spam.