This happened to a coworker of mine, only it wasn't a prod accounting system, it was a prod customer facing system. We got the crontab restored, I though I forget from where. I think we ended up doing a blend of common stuff copied from a sister system, and bringing in other entries from the detritus of an ad-hoc backup that was fortunately still on the system.

My poor cowoker still feels embarrassed about it, even though it's been some years since.