Wrong item sent and situation not rectified

I bought a white duvet set with sheet from her. When it was delivered it was cream coloured. I immediately contacted her and was informed that it was \off white". When I said I ordered white she said the item would be replaced and I should send back the wrong item. After two weeks I still had not received the correct item. I contacted her again as this was already one month after the order and asked for my money back. I also said she could arrange a courier to pick up the wrong colour item as I would not pay to have it sent back. I was informed that I would be refunded on 25 September 2015. It is now 02 October 2015 and I still have not received the refund nor has she sent a courier to pick up the incorrect item."""