Start by taking meter readings, checking whether your bill is based on actual or estimated usage, and confirming the readings and billing period are correct. Next, review your tariff, standing charges, unit rates and direct debit amount, then ask your supplier to explain anything you do not understand or think is wrong. Compare available tariffs using an Ofgem-accredited comparison service, and check GOV.UK for support schemes such as the Warm Home Discount or help with energy debt. If you cannot resolve a billing dispute, follow your supplier’s complaints process before asking the Energy Ombudsman for help.