ntlworld email - not receiving

I cannot get Macmail to receive incoming emails from my ntlworld.com email address for about a week, though gmail is fine. I did not change any settings but broadband went down about a week ago and though now ok this feature does not work properly.
MacBook Pro, Mac OS X (10.7.5)

What have you tried already to re-establish the mail connection? What, if any, messages or errors have you seen? My experience is that a simple stop and restart of Mail will fix the connection.