Proximity sensor doesn't work even after screen and flex replacement

Hello.

I'll try to tell you my "story" briefly.

1 month ago I went abroad and bought me a new iPhone 6s plus LCD.

came home, replaced the screen - The screen doesn't dim at all while calling...

I was thinking what went wrong... my proximity sensor DID work!

Fortunately I had a new proximity sensor flex cable (that also comes with front camera and all...) and replaced to that new flex cable - STILL NOT WORKING!

Tried to seek online for solutions and and I figured out that probably the screen was doing the problem and its a fault. But I can not go to the store and replace it because it was abroad, so I tried all the solutions online to fix the proximity sensor eyepiece in the screen.

Tried to scrap the color and recolor it with a black pen and do a little holes - STILL DID NOT WORK.

This time I gave up and went to buy a new screen, replaced it to the new screen - AND STILL DON'T WORK!!

After that I tried to do an hard reset and reset all settings - STILL DON'T WORK!

I don't know what to do... I am trying to see if the the proximity sensor bracket (the transparent little piece that holds that) doing the problem because he was painted a little bit in black while I was painting the screen eyepiece... maybe I will replace it?

What do you think I need to do?

Thank you