Are you using 10s or 11s?

Many people have been happy using 11s Shimano cassettes with 11s Campagnolo shifters. It is worth trying, and may save you some money on future cassettes.

Can you tell what your hub is?

My guess is this is your freehub body:
Prime R010 - R020 Freehub Body - Campagnolo | Chain Reaction Cycles

They usually are easy to replace, just remove the outer locknut, and it all falls apart.