Yes I have the private key , but 0 coin in the account
Make sure you're looking at the correct account. When you import the private-key it will create another account (the one you just imported) so you need to switch to that account to see your XEM.
Does the client show the correct address (the one you registered) in the upper left corner ?
I know how is work, dev team put me on a sockpuppet case , and I haven't get my coin yet