http://resolutioncenter.ebay.ca/
File an Item Not As Described dispute -- if the lot was supposed to have 4 items but was short one.
File an Item Not Recieved dispute -- if you purchased four lots from the same seller which were supposed to be shipped together, but were not. Check with the seller to see if one was shipped separately before filing the dispute. The seller should be able to give you the date and service of the shipment. He might be able to give you a tracking number, but that service is expensive and more important for him than for you.
