Mail Outgoing blocked.

Mail Outgoing blocked.

Hello, 

I've received the following message:

User : [HIDDEN]

Details :Mail Outgoing blocked. Reason :Daily Mail Bounce Count Exceeds Limit [ Bounce count=20 ] 


I've tried to unblock it from the troubleshooting panel in our Control Panel, but it says :

Operation permitted for paid user(s) only

Can you please help me?

Best Regards,

Gery