First... remove the cleat mount from the boat. That might mean pulling the screws holding the track down. It might be as easy as pulling the screws on the line guide.
Check the bottom for jam nuts applied with locktite... Heat will release locktite.
If that doesn't solve it:
Grind the heads off the cam cleat's screws. Now the cams will pop off.
Now you can file flat sides on the screws and get a really good grip with locking pliers. That will let you get them out.
Worst case... you can have a new stainless mount plate made (or make it yourself if you can get the stainless)
The tracked cam cleats for the jib sheets on my Vagabond are almost identical style.