Which one is correct?
The building was not recorded on the cadastral plan. The building was not registered on the cadastral plan. The building was not processed on the cadastral plan.
Or how can I make it correct in any way?
The answer is less about the English language and more about how your particular cadastral plan is administered. I don't know how property definitions are handled in your jurisdiction, but you could probably find out from those who manage it.
I would guess that "processed" wouldn't apply. Whether "registered" applies depends on whether there is a "registration" process involved with getting something into the plan. If there is no formal registration process, "recorded" would be correct.
While I'm on a roll guessing here, I would opine that "recorded" would always be correct, since it doesn't imply anything about how something would get into the plan. So if you can't be more specific (eg, by using "registered" or some other process-centric word), be correct by being general.