Apple Pay rival CurrentC was hacked during a testing phase as it is being readied for market, resulting in a number of email addresses being stolen.

The Merchant Customer Exchange (MCX) sent an email to beta testers of the technology to alert them their information may have been accessed.

"Within the last 36 hours, we learned that unauthorized third parties obtained the e-mail addresses of some of our CurrentC pilot program participants and individuals who had expressed interest in the app," said Linda Walsh, a spokesperson for MCX. "Many of these email addresses are dummy accounts used for testing purposes only. The CurrentC app itself was not affected."

The news is likely be a blow to the group, which is trying to gain traction in the mobile payment space amid an uprising of popularity for other mobile payment services such as Apple Pay and Google Wallet. Apple Pay launched with the release of iOS 8.1 and has been the center of a lot of attention since then.

CurrentC, which is MCX's mobile payment app, displays QR codes, which can be scanned in retail stores when purchasing items. Many retailers are interested in the new service because it bypasses credit card fees by being linked directly to a bank account. According to MCX, the app will also include things like gift cards and coupons and may leverage Bluetooth technology.

"MCX is continuing to investigate this situation and will provide updates as necessary," continued the group's statement. "We take the security of your information extremely seriously, apologize for any inconvenience and thank you for your support of CurrentC."

MCX requires retail stores to not accept other mobile payment systems, with both Rite Aid and CVS having disabled near-field communications capabilities in the past two weeks. NFC is the technology used with services like Apple Pay and Google Wallet and more retailers that are part of the MCX are expected to follow in CVS' and Rite Aid's footsteps.

MCX was created around three years ago in an attempt to develop a standard mobile payment process. Several large retailers including the likes of Best Buy, Target and Wal-Mart are part of the group. A nationwide rollout of the app is expected in the first half of 2015.