Campy Ergo levers are quite rebuildable, if parts can be found these days the work parts can be replaced. That's one beauty and hassle of them.

Cable adjusters can become corroded in their fittings, common with Al bikes and sweat. Hopefully the barrel will start to be able to be rotated with penetrating oil (not WD40) and some careful pliers action. I've broken off adjusting barrels before doing this so...

BTW do yourself a favor and try removing the cable head from the lever first. It looks to my eyes that a Shimano spec cable head in installed and being slightly larger in diameter then a Campy one often can get stuck in the lever. Not a good thing Andy