Try setting one up with 'Freedom' as a test, to see whether it's a settings problem or a BT connection problem (wrong password for example). Use these settings to set up a dialup connection:
Phone Number: 08456042079
Username: The telephone number you are dialling from
It's charged at the 'lo-rate' of 1p/min at weekends and off-peak, so it'll do for a test. I use it as a backup should my BB connection fail.