I get a call with a pre-recorded message at least twice a week from a different number each time. I've got a routine now. Talk very quietly into the phone for a few minutes until they think I'm on the hook and are listening intently, hopefully with their speaker volume turned up. Then, just when I have their attention, yell something like "STOP CALLING ME, A**HOLE!" as loud as I can into my phone. With any luck the idiots working for these companies will all have to quit from hearing loss before long.