Here is what I do, ask them to speak a little louder, do this about four times until they are shouting into the phone and then say that was too loud speak little softer, do this until they are at a whisper then go back to a little louder please...keep it up until they hang up. Maybe it won't decrease calls but you can have fun. Also I have an alter ego, a very cognitively challenged elderly aunt who always thinks the caller is her nephew Billy....no matter what you keep asking when Billy is going to come visit again be cause his auntie misses him soooooo much.