He refuse to refund me

This guy is soo rude …he sold me brake disk and said he is so 100% sure it will fit to my Porsche Cayenne 2014 model ….when I asked him what if it doesn’t fit he said he is sooo sure it will fit. Few days later I call him to inform no him that my mechanic says it doesn’t fit ….he refuse to refund me or exchange with another product.