I ordered an IPhone 5S refurbished phone on 2nd No...

I ordered an IPhone 5S refurbished phone on 2nd Nov. It arrived but was faulty (shadow on screen, poor battery life). I sent the phone back and was promised a replacement. I've been told twice since following it up that it was due for dispatch but has not been sent to me. I have been waiting since Nov 18th for this now and I still have no idea when it will be sent. I have now been assured it will be with me before Christmas, but have received no confirmation that the phone has been sent. I asked for someone to contact me and they promised to call me today - but they failed to do so. I am so upset with the poor treatment - especially after paying 140 pounds for a phone that I am yet to receive.