Dear Sir or Madam
Ref: [contract number]
I am complaining because I have been charged an incorrect amount for my [mobile phone/ broadband] bill.
When I first learned of this problem, I contacted [name of person, date of the call] at your company.
But I am unhappy with the resolution offered because [add your reasons here].
I enclose a copy of my bill highlighting the charges I dispute.
Please can you send me a revised bill and explain why I have been charged extra in this way?
If we haven’t agreed a resolution before the eight weeks have lapsed on [date], I will take my complaint to a telecommunications ombudsman.
[Type or print your name]