Hi @EmmaWright - Sorry to hear you are leaving Bulb, but according to https://help.bulb.co.uk/hc/en-us/articles/360016075911-How-do-I-leave-Bulb-
We’ll be sent meter readings from your new supplier which we’ll use to generate your final bill. We’ll send you this within 6 weeks of leaving us, and then collect your final payment or refund you any outstanding credit.
So it’ll be just waiting for your new supplier to complete the switch (21 days from the time you join), them sending their opening meter readings (and therefore Bulb’s closing meter readings) to the independent verifier who should then send them onto Bulb for your final bill (the verifier can be slow sometimes and therefore it can take 6 weeks). Once that’s been done, Bulb will refund you and it should show up in your bank account within 5 days (technically, you could get the refund within 23 days of signing up with your new provider: but that involves everyone being ‘on the ball’ and sending things promptly to each other and the timing of ‘batch processes’ being ‘just right’).
What I would do is, since you are in sufficient credit, is reduce your direct debit down to the minimum allowed (I think this is £5) via https://account.bulb.co.uk .