"because I am a customer"

Since being in call center means you are going to get a lot of “i wanna speak to a manager” in your life. I always feel the customers just take advantage of it because they know it’s a tactic to get things done. So one day a guy calls in an directly say to me that he was to speak to a manager. I said ok I will get a manager but what’s the reason he wants a manager i asked politely Now he says” Because i am a customer” The way he said it i wanted to annoy him and said ” but since your account didnt come up on my system, how would I know you are our customer” He fumed and dropped the call. I am not sure if I was right or wrong or didnt know what I was doing but a response like that from the customer would make anyone angry.