bought new continental tyres from Private Person.

I have bought new set of 4(Size 225/45 R18) continental tyres from a private person through gum tree, when we agreed to meet I saw the tyres were new never used as per his ad and he claimed there were new and I was convince this types were new and I pay them and I went to Sherwood Cape Road to fit them when the staff of Sherwood fill in the air on the types there burst on the side & it was discovered this tyres were rejected from the factory but what I don't understand why Continental tyres allow the rejected tyres to leave the factory and sold to the public which put our lives on the high risk because I bought this tyres because of the good brand and there were recommended by BMW to replace my old continental tyres with new one, I failed to understand why this rejected tyres left the factory and put peoples life at risk. I have give back the tyres to the seller to refund me but I have not get back me and I want Continental tyres to replace this rejected tyres with the new one if not I will take this matter to the media due to poor management to allow rejected tyres to be sold to the public.