Poor service and not enough details for what you purchase

I have been trying without much success to be refunded for the prepaid package I purchased from MTN namely this one https://www.mtn.co.za/shop/deals/cash/combo-offer/4012. But upon completing the purchase I was informed that a sim card will be shipped to me. This is not what I wanted, I wanted this package to be added to my current sim card. Nowhere during this purchase does it state that it can only come with a new sim card. So I asked my money back and was told it will not happen. I reported MTN to ICASA who is busy investigating them.