Cable problem

I bought a type c usb cable from them some time last week and I specifically asked the guy Nadeem if it has fast charging for my s8 his response was its not about the cable anyways it has more to do with the actual charger head and I said ok fair enough I will take it.Get in my car ******* the packaging and throw it out because I want to use the cable immediately bearing in mind that it will give me the joy of fast charging and I don't get any in the car ok fair enough my my car charger wasn't built for that I then get home try out the charger again with my original samsung head,still no joy I then go back to Vodacom pavilion opposite wimpy I explain to them that this cable is off no purpose to me and I want my money back they tell me they can't refund my because of a mere box i don't have so they give me another cable that's still doing the same thing!