Beta software stuck on phone

I had a problem with my imessage and have been in contact with apple. I updated my phone as they advised and still imessage wasn't working properly(could send but not receive). Rang again and it turns out my phone is on a beta software-version 16.0.2. It's an iphone 11pro. I never signed up to be a beta tester (I didn't even know what beta was when they told me I had it) and I can't get the beta software off my phone now. If I go to setting-vpn and device management-there is no beta tab there. I have tried doing a restore. My icloud has backed up the phone yesterday but when I did the restore-the beta was there still-I guess the beta was already on it yesterday when my phone backed up to the cloud. Anyone else have this issue? Is there any hope for getting off beta software without losing all the stuff on my phone...years of stuff. Please help