Before you cancel your old Direct Debit, it's best to check with your old supplier so it doesn't disrupt final payments or refunds.
While you are switching your energy supply you may find yourself with two active monthly Direct Debit payments. Rest assured you will never pay twice for the same energy.
Both suppliers will agree on meter readings for your energy supply switch and any money due to you will always be refunded.
Once your old supplier agrees on the final balance on your account they will use your Direct Debit details to collect final payments or refund any credit on your account.
The old supplier should cancel the Direct Debit automatically when they close your account.