A Dunedin woman believes the new self-service petrol pumps at Pak'n Save in South Dunedin are having "teething problems", which have left her with a major cash-flow problem.
However, Pak'n Save co-owner William McDonald denied there was a problem with the pumps.
The Dunedin woman, who declined to be named, said she used one of the pumps yesterday to fill her car.
It charged her the expected $150 "pre-authorisation" fee for using her credit card to pay for the fuel, but the machine stopped before the fuel tank was full.
"It only pumped $23.46 into my car - it was nowhere near full."
She pulled the trigger several times but the machine did not restart.
An attendant also tried to restart the pump but without success.
The transaction was closed and she was asked if she wanted to swipe her credit card again to try to fill her car.
"But I would have had to pay another $150 fee on my credit card, so I decided not to.
"It wasn't a good experience," she said.
Mr McDonald said the machine did not malfunction.
He believed it was user error which caused the problem.
The machine was designed to stop when there was "back flow" or too much "back pressure" in the flow of fuel to the tank.
He believed the machine stopped without the customer realising, and by the time she did notice, the machine had "timed out".
Mr McDonald apologised for the inconvenience, but the transaction had to be closed, and said a new transaction had to be started if she wanted more fuel.
The woman disagreed.
"It just stopped.
"I knew as soon as it stopped.
"When you're holding on to the nozzle, it's hard not to notice."
She was concerned the $150 pre-authorisation fee could cause people with low incomes to "max out" their credit cards - particularly if they have to use it more than once to fill their car.
The $1.3 million unmanned petrol pumping station is supplied, but not branded, by BP.
The pumps take eftpos, credit cards and cash and offer Pak'n Save shoppers discounts on the otherwise standard fuel pricing.