It sounds like you worked hard to keep your prepaid account in pristine shape for two years but are not reaping the benefits of it. One year of on-time payments on a prepaid account should still be sufficient enough to be well-qualified. The deposit required sounds like for the line activation itself not the down payment of a device. You can more info about Smartphone Equality here: Smartphone Equality .
That’s because T-mobile doesn’t care about their customers. They continue to prove it to their customers.