i did a hard reset by disconnecting the negative lead on the battery left it for about hour.  now my xf r-sport wont respond to either smart keys not even the central locking. when i try to start my car i get an invalid smart key response on the dash. i have had the keys checked and there working fine. also unable to pair a new key to car message says failed. only had car about 3 weeks does anyone have any ideas whats going on ?

Have you tried the little port for the key in the lower dash right side of steering wheel? 

my xf doesnt have the key port but i have tried putting the key in the right spot but dash says smart key error

 

The XF does not like having the battery disconnected. When these problems occur Jaguars solution is to replace both the Front and Central Junction Boxes and reprogram - cost over £1k. Find a garage with Autologic software and they will reprogram without changing the JBs normally for under £100.

If you change the battery always connect a slave battery with wires to the clamps so that the car never loses power.

 

Sadly most modern cars are like this now, royal pain