How do I get my credit balance back after closing my account?

Please don't reply with the answer to call T-Mobile or go to the store.  The store people say call the number and the phone support says go to the store.  Both are equally worthless and refuse to help, which is why I left T-Mobile in the first place.  How can I get to someone at T-Mobile that will actually help and not route me to a 3rd world call center where they read from a script.