He told me that he has no space in his house and it suited him me to have it in my house.
How extraordinarily entitled - and to blatantly admit it too. There are lots of things I wouldn't have space for in my house, so I have a very cunning scheme: I don't order them.
As with the PP, I'm baffled as to why you would order a parcel and then not want it ASAP - or at all, apparently.
I'd be very tempted to just put it through their letterbox, ideally whilst they're there in the house. I'm sure it will fit through, even if you have to take a run-up, use a mallet or kung-fu kick or visibly rip it open and then start stuffing it through bit by bit. What valid grounds for complaint could they possibly have when they were standing there and ignored you? I bet that would have them running to answer the door.
It sounds like they're probably hoping to claim a refund for its non-arrival within the seller's specified 'allow X days before contacting us' terms (or an extra free duplicate item), before collecting it from you. Still makes no sense: if they're going to lie and defraud the seller anyway, why not take the parcel in first? The company are hardly going to send somebody out to search their house before issuing the refund, are they?
Bizarrely, they're putting all your trust in your honesty whilst apparently being thoroughly dishonest themselves as, if you wanted to, you could just keep/sell the item, deny all knowledge and then there's not a sausage that anybody could do about it.