I had a problem with FedEx. Document every phone call, screen shots of delivery changes, people you talked to ad nauseam. Obtain any written shipping and notice of delivery documentation from your supplier. Reference the supplier notice of delivery to the FedEx website to compare actual delivery time and date. File formal complaint with FedEx, they have a process on line. If you get "Charles" in Pakistan, demand to speak to USA representative so you can actually start the formal complaint process faster. Do any of your neighbors have security cameras that might show any timelines to confirm any deliveries in your road?
I did get paid but submitted overwhelming evidence of their damage to my yard etc. These processes are designed to be pita but if you follow through, ultimately they know they have to pay.
After a couple delivery issues I saw where someone places game camera in his porch window to confirm an expected delivery. I think its a great idea! Plus for porch pirates.