FedEx lost iMac on Return Order

Anyone ever experienced a return being lost by FedEx. I bought an ultra expensive iMac Pro a month ago. Had issues from the first day, by the third day, it wouldn't turn on at all. Support on the phone told me to return it and get a new one instead of exchange. It would be faster. I did exactly as told. Got the return label, called for FedEx to pick up. The FedEx truck showed up as expected the next day, the carrier picked up the package. I didn't see any update or got a refund for 10 days. Texted with Apple help for over an hour but receive TERRIBLE service. Either it's a robot of the person thought it was funny to just keep repeating the same line, "sorry I know you are frustrated but rest assured, you will receive your refund". I tracked the Apple order which stated the return label was created, but carrier had not picked up. I checked FedEx according to the tracking number, it was the same. I finally got a telephone number and spoke with a customer service and spent another half hour, this person convinced me that I just had to wait a couple more days. I waited another weeks - no update whatsoever. My new iMac Pro showed up and now I am out 2x $15k. I can't. I just can't. I need that refund now. I have been on hold for the customer service line for another 35 minutes right now. It's been a HORRIFIC EXPERIENCE so far. First the computer didn't work and I spent so much time setting it up, and trying it out. Then this return is taking over 2-1/2 hours so far...