Sounds like the lower part of the lock cylinder has snapped off??? If you open your door and look down the edge of it there is a black plastic cover that goes down the length of the door, take this off.
Then there is a small round piece of what looks like duct tape? take this off aswell and inside that you should be able to make out a T20 torx screw, firstly pull the door handle out and hold it there then get your T20 driver and turn the screw in the door anti clockwise this will release the door lock.
Examine the lock cylinder and tumblers for any damage and also make sure it has the end on it?

if you look into the door where the lock was you will see where the lower part of the lock cylinder goes and turns the mech to unlock/lock the door.
Hope this helps
Cheers
Darren