As in tittle, I've already spoke with ~7 people working at T-Mobile, some even don't know IoT, some says that plans intended for cars only and so on. Already don't know where to ask so doing that here.
Worry to here you've haven't gotten what you needed after that many calls. We do have our dedicated page you can get to clicking our Internet of Things | IoT Products & Solutions | T-Mobile link. If you need more specific information, you're welcome to contact an IoT expert using the link at the bottom of that page. They should be able to give you more info about the services.