@yvonne.zannoun 

That are a lot of cables indeed, but the majority has to do with cable TV.

I made a picture of probably the part we need to be focused on, what looks like you ISRA (DSL) hookup.

If i understood your comment correctly, you connected the green cable to the left hand box.

I can not see it very clear, but it looks like this box has 2 sockets that are equal? Then i also noticed a connector on the right side hanging loose of the suspected ISRA point, is this cable comming out of the ISRA point like i try to draw?

If so, you might need to connect this loos hanging connector (1) to the other connection socket of the box you also connected your green DSL wire.

This could work.

But if it still is not working, TMobile needs to send a technician to confirm correct ISRA point and hook you up correctly.

Hi @Pieter_B ,

thank you very much for taking time to answer with such detail. 
 

I think what you highlighted as the ISRA box is probably correct, I tried to make the connection to it too.
The loose hanging wire (1) is not coming from the ISRA box, it’s not clear from my picture.

I will have to get a technician to look at it because nothing I tried worked. Hopefully this doesn’t take too much time because it’s been 2 weeks without internet at my new place, which makes working from home difficult. :(

anyway, thanks again, i appreciate your effort very much!

All the best!