Poor customer service

In February i ordered a duvet set from Homechoice online then i saw i made a mistake as i was looking for a comforter set,I immediately called Homechoice to cancel the duvet set and order the comforter set,To my suprise i received both orders I called Homechoice and received a return reference number then I returned the items on the 16/02/18 and according to Homechoice it was received on 22/02/10 parcel number PA390 847 427 ZA,Homechoice is refusing to credit me and they want a post office receipt which was snatched with my bag the very same week i returned the stock back to them,Please help as I can't afford to pay 3000 of something that I don't have.that I have returned back to the supplier and that the supplier has confirmed receiving.Ive sent through numerous emails with no proper feedback.My email address is **********