Quoted from TimeBandit:
Once they have an issue with your product, *they have paid you*. NOW they are a customer, and you can give them customer service.
My customers get all the time in the world from me. And guess what..they get BETTER customer service if I'm not tied up with crazies all day long.
Oh I agree about crazies. I work with the public everyday. I had one girl go off screaming and writing emails because I answered the phone "good morning, lock shop".
But... don't expect a sale if I have a question and you won't respond.