T-Mobile says 0.2% or around 200,000 of its mobile customers were affected in a data breach in December. Phone numbers, number of lines subscribed to and some call-related information may have been compromised. The company also reported data breaches in March, November 2019 and August 2018. The FCC requires carriers and providers of VoIP services to protect this data, and failure to protect the data can lead to fines. The data accessed did NOT include any names associated with the account, financial data, credit card information, social security numbers, passwords, PINs or physical or email addresses.”]
Source: https://www.govinfosecurity.com/t-mobile-alerts-customers-to-new-breach-a-15681