Switching incomplete?

Hi.

According to your messages, we switched to Bulb for gas and electricty on 7 May 2018. While our previous supplier now shows us a balance of £0 for gas, they’re still taking money by Direct Debit for electricity. Could you please confirm that our switch is complete and we will receive a refund from our previous supplier?

Also, I see that our previous supplier should send us a final bill by 18 June 2018 and they’ll use an estimated reading to calculate it. Yet I submitted readings to you to make the switch. How is it they can use an estimate to work out the final bill?

Many thanks

Owen