Hackers broke into Experian's network and reportedly stole T-Mobile's data. According to Wired, the U.S.-based cellular network sent the information to Experian to perform a credit check on potential customers.

The hack on Experian's network reportedly compromised approximately 15 million customers, exposing their personal details such as names, addresses, birth dates as well as encrypted data that contains information like the social security number and driver's license.

The site sent an inquiry to Experian on what sort of encryption was used, but they did not get any responses yet.

The compromised data dated from Sept. 1, 2013 to Sept. 16, 2015. Anyone who had a credit check for a new line of service or new device within this timeline could be affected, as per the report of Engadget.

The report further stated that T-Mobile CEO John Legere pointed out that bank account or credit card payment information was not revealed, and Experian reportedly said that the company's consumer credit database was not affected.

Whether or not this incident put T-Mobile and Experian's business relationship at stake remains to be seen. CEO Legere said that they would review their relationship with the credit-reporting bureau, but not right now.

"Obviously I am incredibly angry about this data breach and we will institute a thorough review of our relationship with Experian, but right now my top concern and first focus is assisting any and all consumers affected," Legere stated in a full letter letter posted on Gizmodo.

Legere said that affected customers would be notified. Consumers who may have been impacted by the hack are being offered with two years-free credit monitoring and identity resolution services, and to sign up, click here.

"At T-Mobile, privacy and security is of utmost importance, so I will stay very close to this issue and I will do everything possible to continue to earn your trust every day," Legere added.