SIM Card Problem

Good Day for you.
I lives in Saudi Arabia, and we have three SIM card provider here (STC, Mobily and Zain).
I have a rooted HTC One M7.
I faced a very strange problem with my HTC One M7 mobile phone, which is:
A week ago suddenly my phone stopped working with Mobily SIM Card. Then I did the follow:
1- remove Mobily sim card and insert it in other phone and it's working fine.
2-Tried two other different Mobily sim card in my phone and it's not working.
3-Tried other provider STC with my hone and it's works normally.
4-I went to Mobily office to check if my phone become in a black list, then the guy checked in his system and found my phone in white list. So this good :).
5-I tired to make factory restore and even this not works with me. The problem remain the same.
6-Tried to change ROMs and nothing happen as well.
7-Went for service shop to check SIM card port I found it working fine. I thought may be sim card port got damage in one or two pins for example.

So please can you advise what is wrong with my phone and what to do to solve this problem.