US grocery retailer Winn-Dixie Stores has said that some of its stores experienced intermittent outages with the company’s electronic payment processing system earlier this week, which may have resulted in some customers being overcharged.

The company said that on 25 May an apparent communications problem with a debit network may have resulted in some customers being charged incorrectly for their purchases. In most cases, the debit network should automatically reverse the incorrect charges in the following 24-36 hours.

“We are reaching out to customers immediately to notify them of a potential problem with their account,” said Joanne Gage, vice president of advertising and marketing for Winn-Dixie. “Although we are still investigating the cause and scope of the problem, we feel it is important to get the word out to all customers so they can check their bank statements for any problems.”

The company said it is taking immediate action to resolve any issues and will reimburse all fees incurred because of this problem.