i recently imported some products from china with china post air mail and was given a tracking number........ive been tracking it steadily and it has made its way to an "inward office of exchange" in nigeria.......i checked again today and it said "delivery unsuccesful"......has anyone experienced something like this and if yes what should i do?

Yes, mine said same but just before I got worried, it was delivered to the nearest post office to my mailing address. I think this have to do with the website and it does not necessarily affect the movement of your package.