Again what can T-Mobile do? There are regulations, and laws stopping T-Mobile doing what you ask. Also T-Mobile has no control on the OS and software you are using to do anything. If you want those FCC regulations and laws from around the world give me a few weeks and I can probably do about 30-40 with actual references for you. It would actually make me giggle you switch and sometime after that switch you get charged because Whatsapp code is trash and people should have already moved away from them long before Meta bought them.