Bad attitude from the manager

I am a regular client at bridge city chicken licken, when one is paying with a chip card it is clearly stated at the bottom of the slip that NO SIGNATURE is needed, when i asked to speak to the manager to ask why they ask us for the signature, he gave me such a bad attitude, i always hear him talking like that to his stuff, but to call the customer stupi is just not on unfortuantely. something needs to be done about this, how is he in a management position if he doesn't know what client service is... And the sad thing is that i was not even fighting or shouting at him , but the way he spoke to me infront of his staff and other customers is just not acceptable...