A Woolworths payment system error has angered customers around Australia after it generated duplicate charges for transactions made at various stores in March.
Woolworths customers used the store's Facebook page to vent their frustration at the "extremely inconvenient charges" that have left the accounts of some overdrawn over the weekend.
The error is understood to have originated on the end of one of Woolworths' payment processors, Cuscal.
"Couldn't put fuel in the car and go to work because of this!!!" Trav Wilkins wrote.
Another customer, Damien Hammond, posted that his account was "now overdrawn because of a double-up on a transaction ... if I am charged an overdrawn fee I will be sure to pass that cost on to you so I can be reimbursed because of your incompetence".
On Monday morning Putney resident Adam Russell realised six March transactions had been duplicated, to the tune of almost $800.
"I found out about the problem when trying to buy breakfast at a work cafe," he told Fairfax Media.
When he spoke with his bank, ING Direct, he was asked to submit a disputed transaction form.
He has since been told there would be "a resolution by 9am Tuesday."
"Good marks I guess for the prompt call back, but still unclear what "resolved" means to the bank," he said.
Another ING Direct customer who was affected, said he was told the error occurred on the Woolworths end of the transaction and it "was up to them to resolve it".
"Although it was a small amount in my case ($25), the big concern is that card details are kept so long after the transaction. Doesn't instil a lot of confidence in the age of cyber crime," said the customer, who asked not to be named.
On its phone line, ING is playing a prerecorded message to inform customers who might have been affected.
"If you're calling about a duplicate transaction from the Woolworths Group in March, please be aware this issue will be resolved early tomorrow morning," the message says.
A Woolworths spokeswoman said Cuscal had confirmed that "an error at a data centre" had left a limited number of customers with incorrect transactions on accounts processed by Cuscal.
"We are working closely with Cuscal and can confirm any payment errors will be corrected as soon as possible," she said.
"We apologise for the inconvenience this may cause customers. If further information is required, please contact 1300 767 969."
Woolworths could not confirm the number of affected customers.
A Cuscal spokesman apologised for the errors, adding that the company was working urgently to correct them by Tuesday.
"We apologise for the stress and inconvenience this is causing people. No customers will be out of pocket... People should wait for the charges to be reversed or talk to their financial institution with any immediate financial problems."
