Send a parcel with parcelforce 48, buyer claims to not got it but tracking says their neighbour signed

Hi, wondering if anybody can shed a little light on this for me before I begin to panic. I sold an xbox on ebay and shipped it with parcel force 48. Dropped it at the post office on Monday. Seems it didn't get picked up until Tuesday and it was delivered today (Thursday) the tracking states it was delivered with a neighbour at just a few mins before 9am. The buyer states no card was left by parcel force and he's been to his neighbours and they haven't signed for anything. So hes saying he's left with no Xbox. I gave him the tracking for him to check for himself. The tracking doesn't show which neighbour or a signature. Will parcelforce be able to tell me which neighbour it's gone to? And show me a signature? They are closed until tomorrow so cannot check just now. I can't help but feel things are a little fishy myself but I'm not going to accuse any wrong doing obviously. I suggested that it could be a neighbour who works nights or doesnt have children due to the time it was signed for. Surely anybody with children would still be out doing the school run at that time of the morning.

What should my next step be? And where does this leave me with facing some nasty ebay action and being left out of pocket? Will parcelforce refund this? I know that they have a location tagging system which will show me where they were at the time of delivery.. Does that mean it's then the buyers responsibility to sort this with his neighbour or is he still going to win a dispute with eBay when he no doubt opens one against me?

I can't see where it's fair for me to lose out on this as I sent the parcel.. Made sure it needed a signature. Made sure it was covered and paid for upto it's value incase of delivery damage. Anybody who could advise me on this would be a great help