Become familiar with the Fair Credit Billing Act and use it. In cases like this, talking on the phone is pointless. Do everything by business letter. Be aware that in many jurisdictions T-Mobile's required arbitration clause is unenforceable and they can be taken to your local small claims court. Many lawyers will give you some basic advice for free.
This is super strange but there's gotta be an explanation for this. I say you should give our T-Force folks another shot at this. You can reach them by using the Facebook or Twitter links on our Contact Us page. They are super helpful and can shed some light on this.