If you are getting Incorrect Username and Password Errors when trying to Login to your cPanel - please contact Tech Support immediately, and provide them with the following information:
Domain name that you are trying to access the cPanel for:
Username:
Password:
Specific Error that you are getting:
Can you access your actual website:
*********
WARNING!!!
FIRST, you should try RESETTING your cPanel PASSWORD BEFORE CONTACTING SUPPORT!
Here are the instructions to RESET your cPanel Password:
http://www.hostingcheck.com/whmcs/knowledgebase.php?action=displayarticle&id=22