(Bloomberg) -- A group of U.K. energy suppliers have sent a letter of complaint to their regulator, saying they have no confidence in Ofgem’s ability to manage the market and demanding financial compensation for their losses.

The letter, seen by Bloomberg News, details more than a dozen complaints against the regulator, ranging from protests that a price cap it oversees is unfair and “not set independently,” to a claim that forced regulatory changes resulted in millions of pounds of costs for suppliers. 

“Ofgem has contributed to the energy market being brought to its knees, to the unfortunate detriment of all parties involved,” Jo Gilbert, former chief operating officer of PfP Energy, said on behalf of her company -- now in administration -- and four others. “Ofgem cannot and should not be allowed to continue to regulate in this manner with no accountability or consequence.”

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The letter was sent on behalf of PfP Energy, Green Supplier Ltd. and Utility Point, which are now in administration, as well as U.K. Energy Incubator Hub and Neon Reef, which are trading. The three businesses in administration had more than half a million domestic customers between them, according to Bloomberg calculations.

A spokesperson for Ofgem pointed to an address made by the regulator’s chief, Jonathan Brearley, on Oct. 7. 

“Ofgem has been working with industry and government to manage the impact of gas price rises which are putting undoubted strain on customers and on the supply companies that serve them,” Brearley said then. “We all need to be fully focused on the needs of our customers, particularly the most vulnerable.”

More than a dozen domestic energy suppliers have ceased trading since August, a tally that’s likely to rise as gas shipper CNG Group Ltd. is set to stop services to as many as 18 utilities next month. Record gas and power prices have led to the collapse of firms that have been unable to pass on rising costs to consumers because of the price cap.

The letter requests a reply from Ofgem within 20 working days and says legal advice is being sought. “No regulator should be allowed to regulate in a way that allows for no profit to be made by privately owned businesses,” the letter reads. “We expect full financial redress for Ofgem’s failings.”

(Updates with comments from Ofgem in fifth paragraph.)

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