Seller not accepting delivery of a return. what can i do?

[jazzaboo2004]

Before Christmas, I purchased a second hand mobile phone with the desription of few minor scratches. on arrival, the phone was dented in several places and had a small chunk missing out of one corner, the screen had been replaced but was put on crooked. To add insult o injury, the order was placed early december, the seller then ignored me for several days and thus it arrived 12 days later even though i'd been charged for 1st class!!  I requested a return on receiving the phone to which the seller delayed as long as possible and only when pushed by ebay did they accept based on all the photographic evidence sent. I posted the item using the return postage provided well within the time frame and now the seller has not accepted deliver even though the status shows that they have been carded twice. this was over 6 days ago now. I have messaged the seller as well to advise that the phone is awaiting their collection but as guessed they have not responded or acted. please can someone advise what I need to do now as I fear that phone will end up getting returned to myself and I will end up with no refund and **bleep** phone thats not worth half what I paid.  please help.