Around £35,000 has been taken from Medway residents' bank accounts by a faulty online payment system.
The council says 410 people have been stung by the fault, which drew duplicate payments of council tax and parking fines.
Chief finance officer Mick Hayward apologised to all concerned, but said the responsibility lay with Civica – the company that runs the system.
"Civica have had a bit of a problem," he said. "And there are a number of authorities affected. The poor old punters have had their bank accounts hit twice."
But he added: "We've not had two lots of income come through."
It is thought those affected will be repaid in three to five days' time and Mr Hayward said he had done what he could to speed up the process.
He added: “I've sworn at the people at Civica and have given them earache about this, as have a lot of my colleagues around the country. In fairness to them, Civica have acted quite quickly.
"We do apologise to all our customers that have been hit by this, but it's not of our making. I hope it will never happen again."
He added: "One guy was super-angry. He'd paid a £300 bill and £70 fine twice – the parking fine probably irritated him the first time, but to have to pay it twice."
"We do apologise to all our customers that have been hit by this..I hope it will never happen again..." - chief finance officer Mick Hayward
That person was businessman David Keeling, who owns Kent Security Systems in Walderslade, who believes the council should take more responsibility for the fault.
"They've got £370 of my money," said the 46-year-old father-of-two.
"My bank statement says 'Medway Council', so they've replicated this payment as far as I'm concerned."
He questioned whether the online payment system was secure, adding: "I have never experienced anything like it in my life. I think for a lot of people, to have that money taken out of their bank accounts, will cause hardship."
A Civica spokesman said: "We would like apologise to those residents who have been affected by this.
"The company takes any incident such as this seriously and we would like to reassure everyone that we are working with the authority to resolve the error and we are currently issuing refunds for overpayments.
"These will be in accounts very soon. The company has a strong track record and will take the necessary action to correct any operational error."
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