Can not receive cellular sms

Hi!

so, I switched to iPhone from Android this week, two days ago. I have an iPhone 13 with iOS 15. The problem is that I don’t receive text messages from a few of my friends and one of my sons. Other text messages comes through fine. I called my cellular operator (Telia, Sweden) and they made a thorough research into this and saw that the sms was sent and delivered but it’s like the phone don’t accept them, they said. They pushed new settings and all and told me to take it with Apple - so I did get Apple support that scanned my phone (awesome!!) and of course they said it’s my cellular network that is the problem.

so, after some research I found out that some numbers need the international prefix and instead of just using the 0760 it should look like +46 (0)760 so I changed my number in the phone to this, and I changed my sons number but it still doesn’t work.

he has never had an iPhone or IMessage activated and it doesn’t help to de-activate iMessage and FaceTime and restart the phone. The problem still exists. We are in the same carrier network.

the fun part is that if I pop the sim-card into my old phone, it works. All messages received. But not on the iPhone. I can send him cellular sms and he can read them, well, all of them can, and when they reply it says “Sent, Delivered” but I get nothing.

please advice.

kindest regards

Martin