Energy billing error or back-billing

Typical aim: Bill correction / refund
Be specific: dates, times, order numbers, names, promises made, and the resolution you want.
We’ll reference:
Acts & laws: Electricity and Gas Supply Licence Conditions (Ofgem)
Ombudsman/Regulator: Energy Ombudsman; Ofgem
Guidance: https://www.ombudsman-services.org/sectors/energy