I had the USB port fail to work on my 6 week old 1.0L Focus and this seems to be a common problem both here and abroad. There does seem to be a lot of posts on the web with the solution of removing a fuse to allow the port to become useable again.
Most forum's indicate the removal of fuse 67 in the passenger compartment for about 30 seconds. I tried this without success.
I had to remove the fuse in the load compartment [boot] that is protecting the Info and Entertainment display. That is the 7.5 amp fuse number 14.
As soon as it was popped back into place the USB started working again.
My apologies if this had been posted here before but there is so much info on this subject that I thought it worth posting.