Goldwagen Springs Rip-Off

I bought a tie rod for a VW Polo at Goldwagen Springs on Thursday, 15 March 2017 and when I return it on Saturday 17 March 2017, they refuse to take it back. This was not a special order and it is unused and still in original packaging. I am expected to provide reasons for returning this. I am not sure if this is Goldwagen policy to not accept returns and give refunds. If they do, a charge of 20% is levied. Is this in line with the Consumer Protection Act or are they breaking the law?