Watch out for Cryptopia!!!!
I have traded many times at different exchanges but at Cryptopia: now no credit 3 times in a row.
They steal your money!
They do not credit your account and do NOT respond at Twitter or email.
I think you did something wrong , because I have no issues with Cryptopia . It's an old exchange with good reputation and I think they are fair with their users . Did you contact with their support about your issue ? What was their answer ?