1 address with 2 separate accounts

Hi, My mother has a small house on my property with the same address and had xfinity installed last year, she was told then that there would be no problem 2 accounts on the same address. I had a technician come out last week to install WiFi in my house and he was unable to because my mom already has an account on our address but told us that it was possible, if in-house, Xfinity was able to distinguish my address from hers. I’ve now talked to multiple xfinity customer service reps, stopped by the store, now have a second install appointment for tomorrow and I am not hopeful at all that I will get anything other than wrong answers or the run around like I have been getting for weeks.

just to give some more information, my property previously had two addresses 30 or so years ago, one with just the number, and another with the same street number with a -A. When I first set up an appointment for install, both addresses were available to select on the dropdown menu but when I selected the one with -A the system said it wasn’t a valid address. Any help for someone knowledgeable about this would be appreciated.