I have all three carriers but in this instance it was with T-Mobile. I have a old plan that I still pay on my phone (Note 9) and so instead of paying it off (not sure if adding a new phone would change my plan?) the manager at a corporate store went back and fourth with customer care he finally said f it he just said he would just open up a new line as an only data only line he said (I think) to keep my spending limit higher, it would be cheaper to do it this way. Has anyone ever opened a data only line with a new phone? Btw I ended up returning the phone but now, more or less, I want to buy a phone on all three carriers AND I still don’t want to change my old T-Mobile plan. Is this a good idea? Thanks!!