To keep your billing accurate, we recommend supplying regular meter readings so that you're not billed on estimated usage.
When billing a customer, suppliers will give their best estimate as to how much you should be paying for each billing period - and this estimate is based on data taken from past meter readings. This can sometimes result in your account becoming in credit or debit as a result.
If your account is in credit
Your supplier will refund this amount when you switch away or if you've built up a large enough amount, but the supplier can wait until an explicit request is made by the customer before refunding the credit. If you are in credit, we recommend that you contact your supplier and make this request as soon as your final statement comes through when switching.
If your account is in debit
The supplier may delay or block your switch until they receive the money they are owed. This is why it’s a good idea to stay on top of your energy, and occasionally check that your direct debit is appropriate for the amount of energy you’re using. If you find that you owe your supplier money, contact them directly to resolve the balance and allow the switch to go ahead.
Note that as this matter, in either case, relates to personal finances, suppliers like to deal directly with their customers. If you need to contact your suppliers, check out the supplier page from the menu in your dashboard:
Contact Supplier (links to your dashboard in a new tab, from there, click on the contact supplier on the side panel)