You can win.
Choose a company like DHL for your delivery of goods.
DHL is able to give you the full information, who, where and when a person gets your package and they will send you a signature, if you request one.
I had trouble with a buyer, who claimed of not getting a parcel from me.
I had his signature, his full name, delivery date and could proof that he personally get his parcel.
By the way get yourself a witness while packing parcels. You never know, if somebody is claiming a wrong item received.