The Au Bon Pain in the Shops at 2000 Penn has been overcharging some GWorld users since early January, a University official said Friday.

Some students, faculty and staff making purchases on GWorld cards were mistakenly charged up to twice the cost of their orders from January 2 to March 15, University spokeswoman Michelle Sherrard said. An exact figure for the total amount overcharged was not released by Sherrard on Friday.

Ed Frechette, senior vice president of marketing for Au Bon Pain, said Sunday the overcharging was the result of an interface issue with BbOne, the system provider for GWorld cards.

“The problem was that GWorld card swipes resulted in erroneous ‘transmission failed’ notices,” Frechette said. Cashiers at the franchise swiped the cards a second time after seeing this notice, only to later find “the first swipe did in fact go through, thus the duplicative charges,” he said.

Affected students were reimbursed last Friday.

Sherrard said in an e-mail the overcharging may have occurred unintentionally.

BbOne notified the University after discovering the accidental overcharging, Sherrard said. The company proceeded to work with the University and Au Bon Pain to audit the franchise’s sales during the period of reported overcharging.

BbOne is continuing to work with Au Bon Pain to ensure that no future double charges occur on GWorld cards, and all cashiers at the franchise have been provided with additional training on how to work the GWorld machines. The defective GWorld terminals have also been replaced.

“We are very sorry this has occurred, and we and the company whose equipment and software operates the GWorld card system have acted to reimburse or credit those who were double charged,” Frechette said.