Mobile lines orphaned at old address/Tier 2 Manual Account Migration Needed

A few years ago, we had overlapping residential service started at a second property so that we could do work on it for several months while still living at the original property. So a second residential account was opened and they were linked to my Xfinity ID where I managed both seamlessly. When we officially physically moved, we had service disconnected at the original property instead of "moving and transferring" the service. The mobile lines seem to have been orphaned on the old, now-disconnected residential account number even though they are "linked" and we can still see them as lines on the account. Via the website or mobile app, we can't update payments, shop for upgrades, add lines for the kids, or see many details because we are in the loop of the system thinking we don't have mobile service at the current address. They need to be correctly associated or moved to our current, active residential account. I was finally told this needs to be a tier 2 tech support issue because of the nuance involved with the different systems communicating with each other and to make a post here. It's been 3 years without anyone being able to understand or help! Our billing needs to be updated in a few weeks and we can't do that. Thank you in advance!