T-Mobile says it suffered a breach of prepaid accounts as a result of unauthorized access to its systems. The exposed data includes names, billing addresses, phone numbers, account numbers, rate plans and other details. The information could conceivably be helpful if an attacker is trying to steal a phone number, a scheme sometimes referred to as SIM hijacking or unauthorized number porting. The company is notifying victims by SMS; it’s recommending that victims change the PIN associated with their account, although it did not specifically say PINs were breached.”]
Source: https://www.databreachtoday.com/t-mobile-says-prepaid-accounts-breached-a-13442