Damaged product

Extremely disappointed. I bought a musical baby chair last year as a baby shower gift. It was opened last week as the baby was just born. When the dad tried to open the battery part it didn't open. My mother took it back and the sales lady was willing to assist, however the manager wouldn't replace it. She said that there are other damaged goods in the store room and that they would replace the batter part with one of them. I am extremely disappointed, i believe that it's unfair since the problem was with the actual product. Nobody broke it! This was the Toys r us at the Wonderboom junction. I can assure you that i will never shop at Toys r us ever again if this is how customers are treated