If you cannot access your cPanel you are most likely blocked by the server firewall, the main resaon for this is failed password attempts so your IP address becomes blocked as a suspected hacker!
For cPanel you get 5 attempts and for email 10 attempts, you may not even recognise what's happening, if for example you have setup a new email account and the password is wrong then your email client (Outlook perhaps) will just keep trying to access the email server and you will very quickly be blocked.
If you suspect your IP is blocked, please raise a support ticket so we can get the data center to unblock it and add your IP onto the white list.
