Hi peeps. I haven't been posting for a while for one or two reasons but just had to log on and try to give some advice owing to my experiences earlier this year.
Quick advice.
If your provider goes bust take a photograph of your meter(s). Take note of the reading with the date.
If you are in credit then cancel your Direct Debit, don't let them take any more money from you.
Martin Lewis website. Most likely there will be a forum dedicated to each supplier that has ceased trading - the one for Yorkshire Energy (see below) went to 240 pages. There was a lot of useful advice on there.
https://forums.moneysavingexpert.com/
I was with Avro and they went out of business today.
I hope this is useful?
Sorry long post..
My experience: I was with Yorkshire Energy (YE) - a pretty good company. They went out of business on the 5th December 2020. (Obviously not that good though!). I just happened to take readings that day, I always take photos when I read my meters. Their billing system was still running and they calculated that I was £506 in credit.
OFGEM have a bidding process and 4 Energy Companies bid for the 70K YE Domestic customers. Scottish Power (SP) were selected. They became the Supplier of Last Resort (SoLR).
I received emails from SP saying that they were taking over my supply. Eventually in January I could input my initial readings, that is, the readings from the 5/12/20 when YE went bust and SP took over the supply. I honestly can't remember now if it was my electric or gas reading that I could not input. One reading was correctly input.
The other wasn't. I rang SP 3 times over a 6 week period. Waiting time on the phone around 45 minutes. Told that the reading had been input and to wait 2 weeks for it to be shown online.
Each time no reading present. On the third occasion, it's now February. I raised a complaint. SP have so many complaints, many thousands a month, they can't cope.
By the way, emails were a waste of time as was the online chat.
In the meantime, SP had generated their own estimated reading (an industry approved reading in their favour - I was overcharged £10).
By now I'd escalated the complaint process (I think I raised 3 complaints with SP overall).
Eventually they 'fixed' the reading by giving me a credit plus further credits due to all the time I'd spent. SP use SAP for their billing system, it appears to be rubbish!
Next. The credit balance. The YE creditors took 4 months to generate a final bill (I think I was one of the last, I had generated a bill on the day that YE ceased trading but that didn't seem to count).
Once SP 'recognised' that I was in credit - I saw I was in credit on the YE site on the 1/4/21 - It took Scottish Power 4 days to register that I was in credit and then a few days more to send an email to me to say they would pay the credit to me (within 20 working days - that's a month - the start date was anyone's guess!). So possibly 6-8 weeks later.
I think that was when I raised the third complaint.
By then I'd moved to Avro as I hated SP and their prices were going up and Avro were a reasonably big company (580K customers and had good reviews).
I was with SP for 5 months. I felt they were the worst energy company that I'd encountered.
I thought I'd never have to go through that hassle again but here we are!
Octopus and SSE were/are OK in my experience.
If SP is my SoLR again then I will transfer as soon as SP are registered as my supplier.
For GAS -
https://www.findmysupplier.energy/webapp/index.html
For Elect -
https://www.simplyswitch.com/energy/guides/who-is-my-supplier/
I would then move away, making sure that I've paid SP for the energy usage with them and just await my credit from Avro. Fortunately I'll be owed about £80-90 this time.
I hope this helps.