Thunderbird Account Settings problem

[Jim]

Fc12

I'm having problem of setting up email account.

If I use the Thunderbird Wizard it wants me to type in  Email Address 
and Password,

Then goes out somewhere (I'm Assuming to Medicom to get settings) and 
comes back and gives me a default of IMAP server instead of a POP3 
server and I can't change it.

I called Mediacom and they assure me it's not their problem.
Does anyone have any Ideals ?