Hi,
I swapped the upper modules, just to be sure to have covered everything. Nothing changed.
The only offers I have seen on ebay talk about the same issues as mine:
-first, charging problems
-then, phone failure.
So, since Fairphone has refunded my module purchases, I'll get a screen module and see if I can test it within 14 days. If it works, great, if not, I'll return it.
I'll keep you posted!
Thanks a lot for your support in any case!