My refund

I ordered the trouser online on the 12 Sep and it was delivered on the 21 Sep. The size was small and I logged a return on their website, they collected it on the 29 Sep. Since then I have been doing the follow up with them and they said no item received yet and they keep sending me from pillar to post . I even sent them the slip / waybill as a proof that FedEx did collect the item. I sent the email again asking FedEx they sent me an email that as a proof that item went to Gstar. Since they are saying they are still busy with it. Now I need my money i don't need the item anymore I also wrote them the email stating that but they decide not to respond. I spent R2000 on an item I have not received and it has been almost a month