Item not delivered

I ordered towels and a duvet cover (order #***) on 26 Mar 2016, however the duvet cover was out of stock but the towels were delivered anyway on 7 Apr 2016. I wrote to [Email Removed] stating this and requested that I shouldn't be refunded provided they can source the duvet and deliver it to me. I saw that the duvet is now available. I called and emailed on 12 Apr requesting delivery of the duvet cover and to date I haven't received any response or the duvet nor my refund. I find this absolutely unacceptable especially because Boardmans still has my money. The least they could do is just deliver the duvet cover since it is now available and because they have decided to keep my money and not refund it.