I agree that 1&1 sucks, and their tech support is so stupid. The only thing I liked was that they sent me a copy of FrontPage 2003

for signing up to a hosting account with them, i'm not sure if that offer is still existing. I have the business hosting plan.
Anyways, I have always used my domain name, like mydomain.com and my password to login to the control panel. If your trying to access FTP you'd have to disable the front page extensions under domain in the control panel and wait approximately 10-15 minutes and login to FTP, you'd use the same username/password that you were assigned to access front page.