Challenger energy supplier Gnergy has become the first supplier of 2020 to cease trading.
Around 9,000 customers will now enter the supplier of last resort (SoLR) process.
The Hampshire-based retailer was issued a final order in October last year over its failure to pay more than £673,800 in renewables obligation (RO) payments.
Gnergy was listed by Ofgem in December as owing more than £680,000 in RO payments plus interest.
In January this year the regulator announced that it issued Gnergy with a notice of failure to comply with a final order.
Philippa Pickford, Ofgem’s director for future retail markets, said: “Gnergy customers do not need to worry, as under our safety net we’ll make sure your energy supplies are secure and domestic customers’ credit balances are protected.
“Ofgem will now choose a new supplier for you and whilst we’re doing this our advice is to ‘sit tight’ and don’t switch. You can rely on your energy supply as normal. We will update you when we have chosen a new supplier, who will then get in touch about your new tariff.”