Cannot Get Verification Code For a Locked Phone Because Trusted Phone Has a Cellular Update Failure

My phone is one of those defected I phone 7 models, the A1600. A lot of the same models have the same problem: All of the sudden my phone had no service but I could text and call. Then a month ago I couldn't text or call at all, even when on WIFI. On my cellular settings it says "An update is required to use cellular data on this phone." But there is no update. We have a phone that a family member stopped using which is an SE but we can't figure out the password and it might get fully disabled if we try one more time. When we set up the Apple ID for that phone, my phone number was set up as the trusted device for verification, and I can't receive a text or phone call of verification, and I can't change the trusted phone number. I recently asked my friend to see if she could log in on her mac book (my family don't have apple computers) into my account to see if the text verification could go there, so I'll add on to this if it works. Is there any other way I can get a verifcation code or get into the I cloud account of the SE without verification? Sorry for this complicated problem.

Thanks, Sophia