T's on the right track.
Is some of the net still in the actual latch mechanism?
If the latch is jammed then a locksmith might not be much help (beyond doing what T-Cro suggested) might be a job for a mechanic.
The only way I can think otherwise is to try and remove the inner door panel so you can pull on the rods directly and thereby provide greater force on the latch than your key can provide. But I would still recommend having someone push shut on the door while you pull the rod on the inside .
Good Luck!