Your right to accurate billing and a full refund
Key right
Your supplier is legally required to bill you accurately. If you have been overcharged for any reason, you are entitled to a full refund of the overpayment plus interest.
Ofgem Standard Licence Condition 21 requires energy suppliers to take all reasonable steps to ensure that bills and statements are accurate. This includes correctly applying your tariff, recording all payments you make, and using accurate meter readings. Systematic failures in any of these areas are a breach of the supplier's licence conditions.
The most frequent causes of overcharging include: being placed on the wrong tariff after a switch or renewal, direct debit amounts being set too high relative to actual usage, payments being applied to the wrong account or not recorded at all, double-charges for a single billing period, and incorrect standing charges or unit rates applied to your account.
Start by identifying your tariff — the unit rate and standing charge — and checking that it matches what you agreed to. Then verify that all payments you have made are recorded on your account. Compare the units of energy on your bill against your meter readings. Calculate what you should have paid using your tariff and actual usage. Any difference is your overcharge.
If you have built up a significant credit balance — often due to direct debits being set too high — your supplier must refund this promptly on request. Ofgem guidance makes clear that suppliers should not hold onto large credit balances without good reason. If your supplier refuses to refund a credit balance you have requested, this is a separate breach you can complain about.
If you have been charged twice for the same period, or if payments you have made are not reflected on your account, this is a serious billing error. Gather your bank statements showing the payments made alongside your energy account statements. The discrepancy is usually straightforward to demonstrate. Write a formal complaint citing the specific dates and amounts involved.
You are entitled to a full refund of the amount overcharged. Where the overcharge caused you financial difficulty, additional goodwill compensation may be available. Your supplier must refund credit balances promptly on request.
Identify the overcharge
Calculate exactly how much you have been overcharged and identify the cause. Be specific about dates and amounts.
Gather evidence
Collect bank statements, bills, and meter readings that demonstrate the overcharge. The more specific your evidence, the stronger your complaint.
Contact your supplier
Call or write to your supplier explaining the error. Ask them to correct your account and issue a refund within 14 days.
Escalate to a formal complaint
If your supplier disputes the overcharge or does not respond, submit a formal written complaint citing Ofgem SLC 21. Use GL Complaint to generate a letter.
Escalate to the Ombudsman
If the complaint is not resolved within 8 weeks, escalate to the Energy Ombudsman for a free, binding decision.
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Start Your ComplaintFree escalation available. If your complaint is not resolved within 8 weeks, you can escalate to the Energy Ombudsman at no cost. Their decisions are binding on your supplier.