I have a hotspot with a 100gb 5g data plan. The sales man told me that after the 100 gb were used I would switch automatically to LTE network with “unlimited data.”
Observably, this does not appear to be the case. This month I crossed the 101 gb mark, and the internet speed dropped to 0.10 MBS! I have “factory reset” the hotspot device, removed and updated the Windows 10 network adapters, and changed from WiFi to USB tether.
I can rule out issues with the computer because, I can connect my cell phone hotspot (Verizon) without an issue and with 71.1 MBS on a LTE network.
I suspect T-Mobile is data throttling.
I did call customer service. I waited on hold for more than 50 minutes, and then the service person hung up on me!