What should I do if the individual being notified has not been served?

It is important to attend the court hearing even if you have been unable to serve the individual. Inform the Judge about the efforts you have made to serve them.
If the Sheriff attempted service:
The respective authorities will have provided the court with evidence of their attempted service. When you appear in court, the Judge may grant you additional time to attempt serving the papers to the individual. You can request alternative methods of serving the respondent, such as certified mail. In case the individual cannot be located or is deliberately avoiding service, you can also request the court to issue a warrant.
If the police attempted service:
Take note of the date, times, precinct number, and names of the officers who attempted service. Try to obtain a statement from the police documenting their efforts to serve the individual. If someone other than the police made an attempt, make sure to record the dates, times, and locations of those attempts. Upon your return to court, the Judge may offer you more time to try serving the papers to the individual. You can ask the Judge for alternative methods of serving the respondent, such as certified mail. If you are unable to locate the respondent or if they are intentionally evading service, you can also request the court to issue a warrant.