A disabled woman was sent a bill for two years' worth of electricity, which should have been paid by a council.
Valerie Paynter, a kidney transplant patient, is recovering from an operation to her spine.
She discovered the request for £193 when she inspected a flat she is due to move into in Sheridan Terrace, Hove.
The bill said Seeboard had not received any electricity payments since the account was opened in January 2000.
It warned if she did not contact Seeboard within ten days, the supply would be disconnected.
Seeboard admitted an error and said the bill should have been sent to Brighton and Hove City Council to cover the cost of lighting a communal pathway.
A spokesman said the meter cupboard for the lights was inside one of the council-owned flats and that was why the bill had been sent there.
A series of bills and reminders had been sent to the former resident but been ignored.
Ms Paynter, who is on income support and has still not moved into the flat, said: "I told Seeboard I could not possibly owe them the money.
"When I asked what the bill was for, they said it was for public lighting and that, in the circumstances, I wouldn't have to pay it.
"The council was responsible for the bill, which had not been paid for two years, which I find quite incredible."
A Seeboard spokes-man said: "The bill should have been sent to the council and we have con-firmed to Ms Paynter it will be paid by it.
"We apologise for any inconvenience caused to her if she assumed the bill was hers."
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