FP2 kills some SIM cards

As far as i understand you have 3 different problems.

Issue with T-Mobile SIM cards discussed in this topic.

2

You couldn’t recive calls or you couldn’t make calls?

Take a look in this topics:

https://forum.fairphone.com/t/two-sim-cards-cant-make-receive-calls-when-both-are-turned-on-workaround-wait-5-seconds/12118?u=tkos

Take a look here:

You could have been found all that infos by yourself in the forum.