Left with no supplier..

golcheck

Hi,
I'm having problems with my previous and current supplier.
I used to be with British Gas (for both gas and electricity). In March 2018 I switched to Solarplicity with both gas and electricity.
My gas account has been successfully open with new supplier however my electricity account still hasn't.
British Gas has confirmed that my both accounts have been closed.
After many attempts of contacting Solarplicity without any luck I have taken the case to Ombudsman Services.
OS found that my electricity meter is registered under incorrect flat number (I live in flat 6, meter registered to flat 5). They have also advised that I need to contact BritishGas and ask them to update national database with correct address of my meter.
Now, it appears that since March 2018 (8 months) I have been without electricity supplier. I have been paying Solarplicity monthly for both gas and electricity (fixed DD amount) so now my account is almost £300 in credit which they are willing to refund to me.
What shall I do now? Who should I pay for electricity for the time I have been (and still am) without electricity supplier?
Many thanks
Matt

System

Here is a good place to start:

https://www.ofgem.gov.uk/consumers/household-gas-and-electricity-guide/connections-and-moving-home/who-my-gas-or-electricity-supplier