A Crazy But Gutsy Chinese In Canada

I don’t know how many times.. we have to tell people that we are not a pawn shop. They would come in with all sorts of things.. and try to pawn it to us.. even engagement rings .  Even when we politely tell them we are not a pawn shop.. they insist that we should take just about everything.. because we resell stuff. Then they would huff and puff and leave. What else can one say right..?? if you get a customer like that..??