Takealot Breaking their own promise!

I bought JBL C45BT headphones from Takealot. The left side stopped working and I requested that the item be replaced. They had promised that the headphones will be replaced and now all of a sudden they are claiming that the item is not in stock, whereas it is listed on their website. I just want the headphones to be replaced. I don't want an credit nor refund. How hard can this be???? https://www.takealot.com/jbl-c45bt-wireless-on-ear-headphones-black/PLID***5