jazzy1991 said:
how do a person get to know what decision CIC or CBSA has taken on his MOC report or withdrawal of sponsorship
If you mean you reported someone for a MOC then you won't be notified at all. If you are the sponsor and your reported a MOC and withdrew the sponsorship, BEFORE the applicant landed, then the withdrawl will happen and the application will be closed.
If you mean you are the sponsor and reported a possible MOC because your spouse left you, then you may or may not be told of the outcome of the investigation. Most likely you won't be told as CIC doesn't need to inform you about what they decide.