I have a mobile phone number issued by Orange Israel back in 1998. I used it over the years just for bank and Amazon authentication and it had no internet data at all. Just the bare minimum. Few years later Orange Israel was acquired by Partner Ltd. and it is one of the leaders in cellular and fiber internet in Israel. I got a new SIM card without any mobile data.

Recently I needed to upgrade the SIM card and I signed up so that I would have 400GB monthly mobile data.
When I checked browsing using mobile only, to my surprise it just wouldn't connect to the internet. So I thought I would better go to the service center and ask to replace the SIM card to a new one. At the center after inserting the new SIM card it just wouldn't connect to the internet.
My mobile phone has worked with another SIM card that I bought from Partner so the phone is not the culprit.
I spent hours on the phone with customer service but they just can't get it to connect to the internet.
I tried the SIM card in 3 other newer mobile phones but no luck.
Of course I went through all the suggestions I could find on YouTube and the internet with no luck.
My only explanation is that since the original mobile number was issued by Orange Israel back in 1998 and it had no mobile data then, there is something wrong with it that prevents it from connecting to the internet. I suggested this to Partner but I doubt if they would pursue this possibility.

The only solution that I can think of is to sign up with a different cellular provider that doesn't use Partner infrastructures and keep the original mobile number. I might go this route but at this stage I don't want to risk anything as authentication and answering calls is of utmost importance to me.

Please note that I have tried everything published on how to solve this problem without luck. I just need new ideas as to why my SIM doesn't connect to the internet.

Thanks for any good suggestions.