amoun, I know you are trying to help, but your posts at least to me get close to trolling.
Fairphone has a major amount of German users, and for those not getting caller IDs when they use the phone professionally is a MAJOR problem, even if you don’t see it that way.
So for Fairphone not reacting to such a major issue after 4 days is very disappointing.
I bought the very first Fairphone as soon as it was released, and at the time I was very forgiving for slow responses from an unexperienced and understaffed team.
But now we are on FP3 and years have passed and I find it extremely frustrating to find out not that much has changed seemingly with the support responses…
By the way their response to my support ticket was to ask for a proof of purchase as I bought it from Galaxus… like that would make any difference for a software problem that they caused 
Sorry for the cynicism, but I expect professionalism also from people trying to make the world better.