User marked as SPAMMER. Mail Fetch has also been disabled for any active POP accounts.

User marked as SPAMMER. Mail Fetch has also been disabled for any active POP accounts.

I have the problem. I am the administrator for teman.com.ua
One of our accounts has been blocked saying this: 

User : kh@teman.com.ua 
Details :User marked as SPAMMER. Mail Fetch has also been disabled for any active POP accounts. 

I cannot change the disabled account in the control panel as it says that it is for paid users only.
Can you please help?