The best way to let them know you are being mistreated is cancel. If a service charge is more important then you as a customer, then its there call.
Except there's no true alternative when it comes to POTS.
Not only that, maybe she got special bundle pricing with a ETF attached. That she was losing cause of 'address change' even though she still lives at same service residence. Plus if she was a ISP email server user she'd probably lose your email "addy's" even if she called back a few days later to 'sign-up' under her 'new town & address'.
This is one of those things that if your lucky to get a smart and caring CSR you can get cleared up in 1 call.