Won't refund money paid for parts he can't supply

I purchased Car parts from this online supplier at globalpartsonline in March for R3800.00. He sent me one of the items (cost R1800.00) which was damaged and not for my car model. He said he would refund me for everything once I returned it which I did the next day. The other items have never been sent. Now he keeps promising to refund me but never does anything. I am now in the process of taking legal action.