i never had anyone complain, but if i miss a call and feel they need an explanation (maybe because it was important or urgent) then i just apologize and tell them that i have to keep my phone on silent when i work. and i prefer it silent in the evenings when i don't want to be disturbed. or kids are sleeping, etc. for in between i just forgot to turn the sound on (which is what i actually do if i am expecting a call)
that covers most of the waking time, so if they want to argue that's a hint that they are probably not very good friends. and if they are not friends to begin with then i just tell them to stuff it. they are not my boss and i am not here to do their bidding, and i already apologized to forgetting to turn the sound on when expecting their call.