Back-billing when your Direct Debit was set too low

Great Britain · Rules checked 24 October 2026 · Not legal advice

Free tool: Back-billing calculator. Enter the bill date and the period charged to find the 12-month line.

Many back-bills come from a Direct Debit that was set too low for what you were using, so a debt built up quietly. Ofgem's consumer guidance says you don't have to pay for energy used more than 12 months ago if your Direct Debit was previously set too low to cover what you needed to pay.

But I got statements

The detail matters. If the supplier sent you accurate bills or statements during the period showing the true amount owed, it has already "billed" you for that energy, and the 12-month limit is less likely to help. In its 2020 open letter, Ofgem said it was concerned some suppliers refused to apply the rule because customers had received monthly statements showing their Direct Debit wasn't enough, and expected suppliers not to rely on customers spotting the problem. Check what your statements actually said, and whether they were based on real readings.

Supplier duties on Direct Debits

• Explain in plain language how your Direct Debit amount was worked out (SLC 27.14).
• Base it on the best and most current information, including a reasonable estimate of your use (SLC 27.15).

What to do

1. Find the date of the bill or statement that first asked for the shortfall.
2. Use the calculator to see which part is more than 12 months older.
3. Write quoting SLC 21BA and SLC 27.15. Send a current reading so the new Direct Debit is fair.
4. See also Direct Debit too high? Getting a refund.