T-Mobile had a massive security breach, which included birthday information and social security numbers.
Here is a linkto an article on how to protect yourself from the breach.
Also, here is the link provided by T-Mobile:
https://www.t-mobile.com/brand/data-breach-2021
This details the steps you can (and probably should) take to protect yourself because of their recent data breach.
You might also want to consider freezing your Experian, Transunion, and Equifax credit reports.