T-Mobile subscribers across the US have been experiencing network outages that have been preventing them access to both phone and data services. According to a post on the official T-Mobile Twitter page
We’re aware of the current service disruption. Our rapid response teams have been mobilized to restore service as quickly as possible.
UPDATE: 6:00PM PST T-Mobile has posted an update in the T-Mobile Forums regarding the service disruption:
We continue to work on restoring full services for the small percentage of affected Customers. Please stay tuned for the latest updates. We sincerely apologize for the inconvenience that this has caused our customers.