For those with withdrawals missing like me since early Jan, I got a follow up from cryptopia!:

Hi [username],

Thank you for contacting Cryptopia support.

After inspection of your account I can see that the transaction has not been successfully broadcast to the network on the first try and needs manual reprocessing. I have passed this on to be investigated further and resolved. I will leave this ticket open for further communication on the matter. We thank you for your patience.

Regards,
Cryptopia Support