BT payment charges.

[goldfish1]

Having (reluctantly) signed up to a direct debit with BT to avoid their payment processing fee I find I have now been charged the full bill including the �4.50 payment fee. When I initially contacted BT to complain about the charge, they assured me I could avoid paying the charge by arranging to pay by direct debit. I made the arrangements and expected to pay the bill minus the �4.50. Has anyone else experienced this and if so were you able to claim back the charge?
The customer service line closed at 8pm tonight, so I'm unable to contact them directly.