Oct. 29 (Bloomberg) — CurrentC, the retailer-backed mobile-payment system touted as an alternative to Apple Inc.’s platform, was hacked during a test of the technology, resulting in some e-mail addresses being stolen.

Unauthorized third parties gathered the addresses during the past 36 hours, according to an e-mail from Merchant Customer Exchange LLC, or MCX, the retailer group that is running CurrentC. The system, which lets customers pay for items with their phones by scanning QR codes, is slated to officially debut next year.

“MCX is continuing to investigate this situation and will provide updates as necessary,” the group said in the note. “We take the security of your information extremely seriously, apologize for any inconvenience.”

The attack represents a black eye for a group that’s working to win the trust of consumers and gain an edge over the Apple Pay system. CVS Health Corp. and Rite Aid Corp., part of the MCX coalition, stopped accepting Apple Pay last week, putting a spotlight on CurrentC. Prior to disclosing the breach,MCX said that “consumers’ privacy and data security are our top priorities.”

Linda Walsh, a spokeswoman for MCX, confirmed the security breach, though she didn’t respond to a request for comment on the scope of the incident or how many retailers are testing CurrentC.