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Billing Disputes and Overcharging

ComplaintsLast reviewed: 1 April 20255 min

Being overcharged — whether by an energy supplier, a telecoms provider, a retailer, or a service company — is more common than it should be. You have clear rights to accurate billing and to a refund for amounts incorrectly charged. This guide explains how to dispute a bill and what happens if the organisation refuses to correct an error.

Key points

  • You are only legally obliged to pay the amount properly owed under your contract — not more.
  • Dispute a bill in writing as soon as you spot an error — delay can complicate matters.
  • For regulated sectors (energy, telecoms, financial services), there are sector-specific protections against overcharging.
  • If an overcharge is not corrected, escalate through the relevant ombudsman or take the small claims route.

Common Billing Disputes

Billing disputes arise in many contexts:

  • Utility bills: Incorrect meter readings, estimated bills significantly higher than actual usage, charges for a period after you moved out, or back-billing for more than the allowed period (12 months for energy)
  • Telecoms: Mid-contract price increases above what was contracted, charges for services not used or not provided, early termination fees on contracts you are legally entitled to exit
  • Financial services: Bank charges, unfair overdraft fees, payment processing errors, incorrect interest calculations
  • Retail and services: Being charged the wrong price, being billed twice, or being charged for cancelled orders
  • Professional services: Invoices above agreed quotes, charges for work not authorised, or billing for time not actually spent

How to Dispute a Bill

When you identify an incorrect charge:

  1. Act immediately: Contact the company as soon as you spot the error. Note the date, the reference number, and what you were told.
  2. Put it in writing: Follow up any phone call with an email confirming the dispute. State the specific charge you are disputing, the correct amount you believe is owed, and the evidence supporting your position.
  3. Withhold only the disputed portion: Pay the undisputed part of the bill on time. Withhold only the amount you genuinely dispute — withholding a full bill you partially agree with may put you in breach of contract.
  4. Request a full explanation: Ask the company to explain in writing how the charge was calculated and under which contract term it is permitted.

Recovering Money Already Paid

If you have already paid an overcharge:

  • Write to the company requesting a refund of the specific overpayment, with reasons
  • For credit or debit card payments, ask your card provider about a chargeback if the company refuses
  • For regulated sectors, escalate to the relevant ombudsman (FOS for financial firms, Energy Ombudsman for energy, CISAS for telecoms)
  • For smaller amounts, the small claims process is straightforward — you can issue a claim for money owed (a simple debt claim)

Claims for overpayments are subject to the general six-year limitation period for contract claims, so do not delay if significant amounts are involved.

Back-Billing Rules and Protections

Energy suppliers are bound by the back-billing rule: they cannot charge you for energy used more than 12 months ago if the delay in billing was their fault. This applies to both gas and electricity and is enforced by Ofgem. If your supplier sends you a catch-up bill covering more than 12 months, challenge it immediately citing the back-billing principle. The supplier must write off any charges older than 12 months.

For water and telecoms, different rules apply. Water companies can back-bill for up to 6 years under the Limitation Act 1980. Telecoms providers can also back-bill for past usage, though most voluntarily limit this. If you receive any unexpected back-bill, check whether the provider caused the delay (for example, by failing to read your meter or send bills). If the delay was their fault, you have stronger grounds to dispute or negotiate. Always request a payment plan if you cannot pay a large catch-up bill in one go — suppliers must offer reasonable arrangements.

Frequently asked questions

Can my energy supplier back-bill me for a period more than 12 months ago?
No. Under Ofgem's back-billing rule, energy suppliers cannot bill residential customers for energy used more than 12 months ago if the supplier was responsible for the delay in billing. This applies even if the error was in your favour. If you receive a backdated energy bill covering more than 12 months, challenge it immediately and escalate to the Energy Ombudsman if necessary.
The company has sent my disputed bill to a debt collection agency — what do I do?
Write to the debt collection agency (and the original company) formally disputing the debt and explaining that the underlying bill is in dispute. A bona fide disputed debt should not be actively pursued while the dispute remains unresolved. Report aggressive debt collection for a genuinely disputed debt to the FCA (for regulated debt collectors) and Citizens Advice.
I was quoted one price and charged another — is this enforceable?
If you had a written quote that you accepted, that amount is contractually binding. A company cannot charge more than the agreed price without your consent to a variation. If they try to, you have a contractual claim for the difference — pursue it through the complaints process and, if necessary, small claims court.

What to do next

  1. 1
    Dispute an energy bill with the Energy Ombudsman

    Escalate unresolved energy billing disputes.

  2. 2
    Dispute a financial charge with FOS

    Escalate banking and financial overcharging complaints.

  3. 3
    Issue a small claim for overpayment

    Recover overcharged amounts through the courts.

Official bodies and resources

Financial Ombudsman Service

Ombudsman

Resolves complaints between consumers and financial businesses such as banks, insurers, and lenders.

Energy Ombudsman

Ombudsman

Resolves complaints between energy consumers and suppliers, including gas and electricity companies.

Citizens Advice

Charity

Provides free, confidential, and independent advice on a wide range of issues including benefits, housing, debt, and employment.

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Disclaimer

This information is for general guidance only and does not constitute legal advice. You should seek qualified legal help if your situation requires it.