Why does the T-mobile app take up so much space?

do what previous user futil1ty said,

Go to Apps & Notifications.Select See All Apps, Scroll until you find Device Manger or T-Mobile Device Manager (whatever it’s called) and select itHit the 3 dots in the right cornerSelect Uninstall UpdatesSelect OK to Replace the App with the factory version.

Simply put, find the tmobile app and try to revert to factory version.

wait a day or two, and your space will fill again.  In the apps section under 3dots, you can now show hidden apps.  

You will find there is a hidden version of the same app called com.tmobile.pr.adapt etc.

You will find the cache now is holding 12GB or more of data, the same problem you thought you solved just days ago, yet the phone fills up all over again and the original app isn’t there.  

All the space is under cache but, the clear cache button is disabled.

The only solution I found that didn’t require jailbreaking or rooting phone and losing all data was to download 

adb program.  putting the phone into debug mode (look it up) and running a command in CMD on windows while phone connected to computer to clear all caches.  This actually cleared the missing 12.8 GB I was losing to this hidden app (com.tmobile.pr.adapt) and it has stayed clear since.

Descarga la Android SDK Platform Tools and extract it to any convenient location It shall give you the platform-tools folder.

After that, enable USB Debugging on your device and connect it to the PC via a USB cable.

Then head over to the platform-tools folder, type in CMD in the address bar, and hit Enter. This will launch the Command Prompt.

so like this

c:\platform-tools  (current directory in command prompt)
run command     adb devices
run this command after

adb shell pm clear com.tmobile.pr.adapt

to be more clear, i put adb to c: drive.

I ran CMD as admin.

I changed current directory to C:\platform-tools from the command line.

I typed:  adb devices <enter>

I typed: adb shell pm clear com.tmobile.pr.adapt <enter>

and phone rebooted.

I may have found this didn't work so I googled a way to just clear all caches with this command.  Not sure, it was a while ago, I just know I had to fuss around with command based on errors etc.

This isn't a perfect post, it was months ago.  I know the command 

adb shell pm clear was the answer, but based on errors, I googled and eventually got the command correct and it worked.

I found that I may have cleared ALL caches, and so had to log back into many of my apps and websites I frequently visit etc.  The main thing was I did not root, I did not lose any data other than logins having to be retyped etc. All contacts and important data was fine.

This was a Metro-PCS phone where tmobile app just showed up and ate all space.

I also found with my unlimited plan I've never used more than 200 megs for last 7 years but when this app showed up suddenly my data usage spiked way over 2GB (i'm being conservative with this amount)  so it was uploading data.  I suspect this contained recordings of my conversations, texts, images etc.