The best option is to return it for a refund. There are probably a lot of other issues with the bike: bearings in the hubs, bb and headset are probably not in great shape, tires are probably due for replacement and the bike has generally been abused and not maintained, even if the issues in this already long list are addressed.
Get your money back in full, cut your ties and call it even. Never deal with this shop again and go find a bike at a quality shop.