Bad Service

I bought 2 way baby carrier at Baby City-Savanna and when i got home my baby couldn't fit inside it.I took it back to the store and the assistant manager checked and said is fine i can go and exchange it.While i was still busy shopping she came to me and told me that the carrier is dirty and they wont accept it.I asked why now because she checked it first and said is fine and she told me that her manager is saying that my baby has vomited on the carrier hence they cant take it back.I asked her to call the manager and at first she refused but when i got next to the door she called.The manager told me that the assistant manger should have checked before and she denied ever saying my baby has vomited on the carrier. I tried to explain to them that i have no idea of the white dot that is on the carrier and if i knew it before i wouldn't have bought it back. I was told there's nothing they can do on their side. I don't think i will ever go to that shop or recommend it to my family or friends. I'm so disappointed in them.I was not looking for refund but exchange because now i'm stucked with carrier that my boy doesnt fit.