GLASSBORO, NJ (CBS) — Several students from Rowan University in Glassboro have been charged in a fake merchandise return scheme costing a 7-Eleven store just off campus $35,000 in losses.

The scheme involved Rowan pre-paid debit cards. Students can go to nearly 100 vendor partners and swipe for merchandise. The university cuts a check to the vendor, but a 7-Eleven partner noticed that its sales and what the checks cut by the university to the store just weren’t adding up.

Joe Cardona, Vice President of University Relations for Rowan University, says “If fact what had happened was it had been going on for nearly 10 months, but at smaller quantities, so it was sort of the folks at 7-Eleven really didn’t notice the difference until the numbers got high.”

Police say a 21-year old Rowan student who worked at the convenience store credited his student debit card account, and accounts belonging to his friends, with fraudulent merchandise returns.

Nine students were charged in connection the theft scheme.