The CEO of T-Mobile issued an apology following a cyberattack that jeopardized customer information.

Mike Sievert, CEO of the company, said some social security numbers, names, addresses, date of births and driver’s license/ID information were compromised.

However, he stated that no financial information, such as credit or debit card numbers, was compromised.

“To say we are disappointed and frustrated that this happened is an understatement,” Sievert said. “Keeping our customers’ data safe is a responsibility we take incredibly seriously and preventing this type of event from happening has always been a top priority of ours. Unfortunately, this time we were not successful.”

Sievert went on to say that he is “truly sorry.”

Sievert claimed he couldn’t get into details about the investigation about how the cyberattack occurred. However, he said, “this individual’s intent was to break in and steal data, and they succeeded.”

T-Mobile is working with law enforcement to get to the bottom of the attack, Sievert said.

In the meantime, T-Mobile is offering two years of free identity theft protection to affected customers.

Sievert also announced T-Mobile entered into a contract with a cybersecurity firm to try and prevent future attacks.