Pool Timer gone wrong

Today I bought a pool timer at Builders Warehouse in Gleneagles, when I got o my car I could not contain my excitement so I decided to open the packaging to find that it seem to be old, dirty and had pieces missing as if it was second hand, I went to the returns department to exchange it. The lady behind the counter then said she was going to call someone, after waiting and arguing for several minutes the manager arrived who then very rudely said he would not exchange my pool timer and vaguely made the accusation that I was trying to swop an old one for a new one free of charge. He then kept my timer and refused to let me exchange it for another as he said he would have to consult with the suppliers first. I was confused what I the customer had to do with the incompetence of Builders and their suppliers. I left Builders disillusioned, with no pool timer and a degrading accusation on my shoulders.