Welcome to the site. thumbup
Unfortunately the cam chain breaking can lead to other issues within the engine that you must be aware of. Chances are that the valves will be bent, valve guides damaged & pistons damaged. In a worse case than that, there have been cases where the block has cracked.
It may also be useful for you to know that most people that have had the chain snap report back that the engine is never quite the same again. Oil leaks or excessive oil usage are common.
I don't know what it is about the z22se engine but a lot of garages seem to shy away from working on cam chain repair issues too.
Sorry to be the bearer of bad news but I do hope that you can get your car back on the road shortly. Have you thought about trying to source another engine?