Router return

I went to the Xfinity store in Avon Indiana to return a router. I just updated the one I had. I stood in for a short period and then I gave the router to an associate which told me to get in line. I told him I am just returning my old one I am still a Xfinity customer. He then said I don’t care get in line. Well I sat the router down on his desk and told him my address is on the box take the return please and have a nice day. He then told me I would be charged for the router. I hope that is not the case. Very unprofessional location. I should have just dropped it off at a UPS location. Very unprofessional associate. [Edited: "Personal Information"]