customer 56 (wasting time)

Quick thought, how come a customer will see an advertisement on tv, come in ask about the advertisement on tv, leave come back and dictate everything they know about the advertisement on tv, leave and come back again and set up everything according to the advertisement that they seen on tv, were explained and even explained back to us and everything is correct then in a month start complaining claiming everything we told them was wrong when they told it to us to? Does this make any since? I do not understand how you can know everything yet claim you didn't and that we are wrong.