Debit Card Users Accidentally Charged Double

An undetermined number of Commerce Bank debit card users got charged double on purchases this week because of a "computer malfunction," a corporate spokesman told ABC News.

Commerce Bank discovered an undetermined number of "double charges" when it posted debit-card signature transactions from Nov. 22 and 23 to customer accounts this morning, spokesman David Flaherty said.

ABC News became aware of the problem after viewers complained to the ABC-owned station WPVI-TV in Philadelphia about the double charges.

Customers who were affected by the glitch received credit for the errors within three hours of the glitch being discovered, Flaherty said.

Flaherty added that the bank still is attempting to discover the total number of people and transactions affected by the glitch, as well as whether the error occurred on Commerce Bank's systems or that of its debit signature partner, Visa.

ABC News' Dan Arnall contributed to this report.