Waiting on refund for returned goods for 3 months

I ordered a 10 piece duvet set in December, I returned the parcel on 22 January 2015 because I was not happy with the quality. I have been following up since the beginning of March to try and get my refund and I'm being told that Homechoice hasn't received the returned parcel. I have tracked with the Post office and it shows that the parcel was delivered to Homechoice on 9 February 2015. The agents are extremely rude, they have told me there is no way of escalating except through them, in particular an agent named Bridget. She told me it's fine I can go to hello Peter when I told her that I have sent the receipt 4 times via fax and 3 times on email. I even get calls for the specials, they want me to come and buy and yet no-one is attending to my query!