Prior T-Mobile data breaches
https://www.bleepingcomputer.com/news/security/t-mobile-data-breach-exposes-customer-personal-financial-info/
T-Mobile has announced a data breach caused by an email vendor being hacked that exposed the personal and financial information for some of its customers.
In 'Notices of Data Breach' posted to their web site, T-Mobile states that their email vendor was hacked and an unauthorized person was able to gain access to T-Mobile employee's email accounts.