In reply to FesteringSore:
The best approach would have been to reject the parcel.
The second best sign the note that the parcel was damaged and taken a photo.
If you have done neither, it is the sellers problem, who will have no redress with the carrier, because you signed for the
parcel as delivered in good condition.
The carrier is now off the hook.
I would advise you contact the seller ASAP and possibly get a neighbour to check inside package as there may actually be nothing damaged at the end of the day.