Reading the original post would remind one that Karen has already had multiple interactions with Bell. Most have been negative, and she has referred to some as "retaliatory". In other words, these paths have been tried and failed.

Did Karen's equipment change? No.

What is different is the analog signal that worked in her old environment but not the new.

This issue is beyond Karen's ability to solve on her own. If not her, then who else?

I have fibre in my neighborhood (less than 20 years old), and yet I still have a supported POTS line wired through my house that works with old phones.

So we know Bell is able to supply a D-to-A facility in at least some modern locations. If Karen's new location cannot do this then IMO they're breaking backwards capability. Maybe it's Bell, maybe it's the wiring in her building, but it's not Karen. In any case this situation arguably contravenes Canadian laws on accessibility IMO unless Bell can find an all-digital solution that addresses Karen's needs.