At that point I would either be switching providers to someone who didn't mangle my signal (because that's effectively what this is), or if that for some reason

At that point I would either be switching providers to someone who didn't mangle my signal (because that's effectively what this is), or if that for some reason wasn't doable, I would at least install a VPN to a known secure, untampered connection (like my home router) and route everything through that connection. Having someone intercept my signal and process it behind my back is simply not something I would tolerate from any communications-service provider I employ.