Raleigh, N.C. — Shoppers who bought items at Macy's department stores a few days before Christmas might have paid more for their purchases than they thought.

A software error caused Macy's to double-charge customers who made debit card purchases during a two-hour period on Dec. 20. It was unclear how many customers were affected, but the retailer said it is working with banks to cover any overdraft fees that were charged to customers.

Macy's has six stores in the Triangle – two each in Raleigh and Durham and one each in Cary and Fayetteville.

The incident marked the second time in recent months Macy's has had double-billing problems. A similar glitch in October caused hundreds of customers to complain to the retailer.

Shoppers were encouraged to check their bank statements and to call the bank about any errors. Customers shouldn't go to a Macy's to dispute any billing errors, officials said.