If you pay by monthly Direct Debit your account will sometimes be in credit if you've used less energy than your monthly payment amount. This usually balances out in months where you use more energy (so you don't pay higher bills in winter than in summer).
If a statement shows you're in credit that could be due to the season. For example, you may have built up a credit during the summer that you'll need to pay for the extra energy you may use during the winter - that's why we don't issue a refund automatically.
If you would like to request a refund for credit on your account, please contact us