I'm expecting a parcel sent out from the USA on 28/01. At first FedEx showed delivery by 6pm Mon/03/02, after this time they changed the delivery date to N/A.
Tracking shows the parcel is sitting at Stansted airport now for 6 days, since Thursday. When e-mailed FedEx customer service, after redirecting my e-mail, they told me about their shipping rates and other bull###t, but no info about the delay.
As other customers have noticed they may be manipulating location and arrival times for some reason, and show delivery date N/A as a cover up. The long tracking number is totally useless if there is no info available.