I want my money back...putrid service. Beyond dissatisfied

I've made a purchase on the 29th for takealot using payfast to make payment. They keep sending me emails but can't fix issue. Gives me Opt pin but keep saying invalid. I tried calling them but they wouldnt take calls regarding payment. I had to purchase my items using a different option spending more money. I want my money refunded back to me of R734.00.