As a long-term customer and somebody who is an industry that loves layoffs, so I have been there! Sorry to read all this and hope you took a good package for yourself.
Also as a customer, I now understand why it takes FOREVER to get answers, NO follow-ups, and getting bill issues sorted out is really painful. Lots of lost knowledge, no doubt.
For any T-Mobile leaders reading here, get your act together! Customers are PAYING customers and you need to take care of them. AND do what you promise. AND get more efficient processes in place. AND train the people who are working there now. AND especially, remember that PEOPLE are going to make the business succeed or fail. Starts with you ... treat them well.