Hello,
Thank you for contacting us about a forgotten username and password. I recommend first regaining accessing to AMP (Account Management Panel). Here is our guide on How to login to AMP. Your email address is the username, you can Reset your AMP password via email.
From AMP, you can login to cPanel, or reset your cPanel password.
Then, in cPanel you can reset your WordPress password from phpMyAdmin, or via FTP.
Let us know if you have any further questions.
Thank you,
John-Paul