Now Concrete Floor Poured - Now a gap at the door

We have an older shed which has a simple fiberglass door.  The  door had rested on a wooden sill.

We recently poured a 4" concrete door and the door will now rest on the concrete. 

Of course, the door will no longer close completely.  We now having a 2 to 3" front to back gap between the top of the door and the wall.

And of course, they poured the lower end of the track under the concrete  

I gotta feeling we're going to completely re-install the door track.    

Or is there another solution available?  Some kind of extension?

TIA

Ross

Since the floor has been raised the door is most likely going to have to be reinstalled.