You might check with a store for a new SIM and maybe try resetting network settings on the phone.
You can change the phone model online and it should update in the app. But to this day I switch between 3 phones and TMOs system rarely displays the correct currently used phone.
Hello Jacqueline, I assure you this is simply a common error that happens when switching to T-Mobile ONE or any new rate plan for that matter. What happened was the representative who processed the rate plan change may not have made sure that the T-Mobile ONE data plan is attached to your line. It's mainly an issue when switching from a grandfathered Simple Choice plan. The data feature "falls off" essentially and just needs to be clicked back on.
The fix is simply getting a hold of Customer Service so they can see that your data SOC is missing. I know you've tried and prefer the chat method (I personally do too). I would attempt the chat method on a laptop or desktop computer where you can wait for a rep. If not, calling is always an option. @