I realize that some time has passed however it is very rare for a package to go completly missing. Usually its sitting in one of the warehouses without the tracking info attached to it any longer. Since the staff dont know what to do with it, it just sits. UPS should be able to give you the last tracking location. We just had this same issue with one of our products, it was a multi-piece shipment and one of the boxes was lost. It took Fedex about 8 days to sort it out. I would work with the engine builder and push them to get UPS’s tracking department to do a physical search. They dont like doing them but if you push hard enough they may still be able to find the package. I’m not picking sides but its not the engine builders fault that UPS lost the package. Its unfortunalte that it wasnt insured for the correct value but I dont think the engine builder was malicious in their intent. I would push UPS hard to get your package found and returned. Just my two cents. Good Luck.