Thousands of Simplicity Energy customers will switch over to British Gas this week, after the firm collapsed, leaving 50,000 households without a supplier.
Ofgem said British Gas Evolve – the energy giant's online-only brand – will supply Simplicity Energy's 50,000 customers, with the switchover already underway, having started on January 31.
Customers are being advised to take a meter reading, however your energy will not be cut off during the transition period.
Any credit you have will also be protected. British Gas Evolve is in the process of getting in touch with all households affected.
Ofgem said customers will be able to switch to a new supplier once they have moved across - although this could take up to three weeks. It's yet to share details on the terms and conditions of the new tariff.
British Gas Evolve will honour all credit balances. You can continue to use this to offset future energy use, or request a refund.
Ofgem says if you owed Simplicity Energy money, you should wait to hear from Simplicity Energy's administrators or from British Gas Evolve.
You'll need to repay any debt on your account that you've accrued up to January 31 to Simplicity Energy, its administrator or to British Gas Evolve.
Should I cancel my Simplicity Energy direct debit?
No, but if you have already cancelled it, British Gas Evolve will be in touch to reinstate it over the next few weeks.
Those who haven't cancelled will have their details transferred to British Gas Evolve automatically.
What happened?
Green Network Energy and Simplicity Energy collapsed last week after falling into arrears with the market operator Elexon.
This meant they didn't have enough credit to cover the cost of trading gas and electricity to customers.
Green Network Energy's 360,000 gas and electricity customers will move over to EDF in the coming weeks.
Peter Earl, head of energy at Compare the Market, said: "The energy market is not immune to the tough environment many businesses are facing as the pandemic continues to take its toll on the economy.
"Green Network Energy and Simplicity Energy customers do have options though, and once they have made contact with their new supplier, they can look around the market to find a supplier, service and price that works for them."
Households on a pricey standard variable tariff or those who think they could save money on their bills are encouraged to use price comparison sites to see if they could cut costs by switching supplier.
To find out the best deal for your household, see our guide on how to switch your energy supplier.
