Sounds like the cables came loose from the fasteners that hold them to the derailures.
Put the levers in the lowest gear position and manually move the chain to the smallest chainrings
Loosen the fasteners.
Wipe the cables clean to make sure there is no grease on them.
Use a plyers to pull the cable snug.
Tighten the fasteners again. Make sure the fasteners are tight.
That should do it.