Exactly, woof - what does it say on yoru PoP, eastern, it terms of house number? If you put the wrong number on the parcel then it's your fault - let's hope that if the person at the wrong number doesn't know the person at 39, they'll return to sender so you get it back eventually (that is, if you put your return address on the back). He's not being awkward, he's quite right, it's not the buyer's place to go round chasing his parcel, it's your responsibility to address it correctly. You're not having "problems with the buyer if" this is the case - sounds as if you mailed it to the wrong address.