Do not be afraid of your coins on HITBTC , I also trade on HITBTC and it always takes about an hour until the funds are deposited to my account wallet . Maybe you have some additional transaction information (TxHash etc.) to show it to their support .
You
should be cautious with any centralized exchange. I learned my lesson with Bittrex not too long ago during their account suspension debacle.
As for HitBTC, perhaps my case was atypical but my first and only experience with their support was quite bad. It took them 6 days to respond to a support request and the response might as well have come from a bot. Sure, 6 days isn't as bad as Liqui and Polo's almost non-existent support but it's bad nonetheless.