Banks typically have a failsafe measure to protect against double charges, but it is not clear whether the malfunction bypassed the protective measure.
The system malfunction came during the peak of the pre-Thanksgiving grocery rush, according to multiple sources within the company.
Robin Miller, spokeswoman for Winn-Dixie, said the problem is company-wide.
The Jacksonville, Fla.-based chain has 485 stores across the Southeast.
Company executives are working through the holiday to determine the problem’s source.
The malfunction is believed to stem from one of the steps an electronic transaction goes through after a customer swipes his or her card in the checkout line. Information stored on the credit or debit card is read by the machine, encrypted and sent to a processing company. The processor sends it to the customer’s bank, which verifies the information, approves it and returns the encrypted information to the machine at the checkout counter.
Because banks are closed for Thanksgiving it is impossible to determine the number of customers charged twice, sources within Winn-Dixie say.
Winn-Dixie will correct any excessive charges and is committed to making it a no-hassle process for the customers, Miller said.
The Winn-Dixie customer call center number is 1-866-946-6349.
Contact Star staff writer Jason Bacaj at 256-235-3546