By the looks of things it seems as if Cryptopia is going under....fast...Everyone is missing deposits, support is non-existent. Yet, from the looks of their social media everything seems to be running fine, hell, they're even adding new coins! (of which you lose your deposit when you send it). No word from support on any public platform about the massive amount of people missing funds for weeks. Honestly, it's feeling like Cryptopia went from decent to a complete scam overnight.
I have used Cryptopia only for Electroneum once. Haven't faced any issue though. But yeah, never trust these small exchanges, In fact its difficult to trust any exchange for that matter after the Mt. Got Case. Normally you can get small coins into Cryptopia by paying around $25000 if I'm not right.
But talking about OP's problem it could be a bug that caused this. And due to holidays the support would have been limited. Try checking their twitter or reddit for any updates. I faced a similar issue on Bitfinex XRP withdrawal. I was charged fee of 0.02 BTC. The support still hasn't responded back.