Takealot not wanting to refund me due to a weak plastic zip of the bag

I purchased soccer nets for my son. It coated me R1000. On arrival I noticed the nets were way too big. I ordered the wrong size. When opening the bag the zip came off the rail due to the zip being plastic. The zip can be placed back but I didn't want to ruine it. I then returned the soccer nets and bought the correct size which was smaller. Takealot collected the first soccer nets. Takealot then returned the soccer nets saying I broke the bag at the zip. So I have never used the soccer nets, only checked the size. The bag however, being made with a plastic zip was now the reason why takealot would not take back my order. I felt so angry because I cannot use the soccer nets and it coated me R1000 and by law the consumer should take back the order because it cannot be used and the bag is of weak quality.