Poor quality and bad customer service

Long story short. I ordered linen online form Volpes. I currently have the Egyptian Cotton range on my bed and am very happy with it. I ordered the incorrect size duvet cover. I went instore (Ballito Junction) to exchange for the correct size. They told me that they didn't have the size I wanted and didn't know when they would get it in again. I asked them if they could order it and they said that because it was an exchange and not a new order, they couldn't do that. I went in a week later to check if they had received stock, still nothing. They offered me (the more expensive) Supina Cotton Range instead. Because I like all my linen to be the same, I exchanged all the Egyptian Cotton bedding that I ordered (pillow covers x4, sheet and duvet cover) for the more expensive (and hence better quality surely?) range. I put the linen on my bed and after sleeping on it for about a week, I noticed that it started forming fabric pills. I had my previous Egyptian Cotton linen for 5 years and it was still in perfect condition. I took the linen back to Volpes to ask for an exchange back to the Egyptian Cotton range as I was not happy with the Supina range quality. My linen was sent to head office and they came back to say that they would exchange the duvet cover because there was a manufacturing defect (faulty studs, which I note my previous duvet cover also had) but because the pillow covers and sheet had been used, they would not allow an exchange. I explained to them that the sheet and pillow cases had obviously been slept on as this is how I became aware of the bad quality. The last email I received from head office was 19/01 and after numerous follow ups I haven’t heard back from them even though they still have my ‘used’ pillow cases and sheet and I am still due an exchange for the duvet cover. This has left an extremely bad taste in my mouth as I have always valued the quality of Volpes yet when it comes to customer satisfaction they don’t seem to be bothered.