The summons and complaint (complaint is the lawsuit attached to the summons) should have a case number.  You can't file an answer to the complaint with the court without knowing the case number.  Since the court has no record of the case, that means it was not filed with the court.  It could be served by the private investigator or any other process server, and not necessarily by the constable.  The case should be assigned to a judge, but procedures vary from state to state as to when that occurs.  The court stamp and case number should be on the summons and complaint if it had been properly filed with the court.  It is not notarized.Since the case was not filed with the court, you don't need to respond.  As mentioned above, you can't file an answer to the complaint with the court without knowing the case number.  If you contact the attorney's office, the attorney will correct these problems and have it re-filed and served on you.  By not contacting the attorney's office, you can delay the process since they won't be able to proceed with the case until it has been properly filed with the court and served on you.