As many as 4,000 financial services customers may be at the centre of another embarrassing mix-up at the problem-plagued Canadian Imperial Bank of Commerce.

According to a report in Wednesday's Toronto Star, thousands of President's Choice Financial customers were mistakenly billed by Canada Revenue Agency after the CIBC -- which administers the Loblaws banking venture -- gave the federal agency "incorrect information."

CIBC spokesperson Susan McDougall told the paper the mistake stemmed from an "an error in the data file," that resulted in the federal tax agency believing the bank's customers had cashed in part of their tax-sheltered savings in 2003.

That adjustment to between 3,000 and 4,000 customers' registered retirement savings, or RRSPs, prompted the federal tax agency's automated process to send reassessments demanding cash back with interest.

CIBC and Canada Revenue have met to discuss the problem, and say affected customers will be contacted with notice not to pay the bill. Then, new reassessments will be conducted.

In the meantime, those who were billed should just file their 2004 tax return as usual.

Word of this latest mix-up comes as the bank is still reeling from the revelation of a privacy breach last November. The bank's chief executive apologized after it was learned a glitch saw faxes with confidential information sent to a U.S. junkyard and a Montreal shopping-cart company.

Shortly after, the bank was again forced to apologize after one of its automatic bank machines spat out Canadian Tire money in place of legal tender.