What should i do if the item is incomplete where as it was sold as complete?

BrickPick3r · 2013-12-03T05:17:29.000Z

I need some advice from experience buyers and sellers. I recently bought a used lego set stated as 100% complete. But after i build it, one piece is missing. It's a common piece that can be found on brick link. But it's a bit troublesome to just order one piece. Could anyone give me some suggestions? Should i let the seller know or ask him to search for the piece for me? Or i should just accept it and go for brick link? Thanks