R4000 deducted from Credit Card without permission

I ordered a bottle of slimming tablets and I was billed for R4000. I immediately stopped the order at the bank and the merchant. the order was never cancelled as the merchant cashed the money. it was meant to take 4 days for the product to reach me. It has been 4 weeks I have no products and no refund either. every time I try reach them via mail their story is different.