They probably haven't received it.  International shipping doesn't happen overnight.  The tracking number becomes active after the system arrives at a Fedex logistics site in your country.  Until then, it's on the way from the manufacturer in China or Mexico to there, and the number remains inactive.  
Placed an order and it said the build was complete,  and it was shipped, but I go to tracking number on fed ex page and it's saying dell never gave them the package. Not sure what's going on,  getting conflicting information from dell and fed ex. 
Shipped, but FedEx says they never got it from Dell