How do they not know if someone was served properly or not?
The person conducting the service submits a "proof of service" affidavit to the court. The court does NOT send out an investigator to double check the service, they rely on the statement (signature) of the person conducting the service to affirm that good service was conducted. It is not entirely uncommon for matters to come to court again over an allegation of improper service. But, until you or your mother make an issue out of this IN COURT, it's not going away.
Since you admit you were aware of the court hearing and chose not to attend, you may be dead in the water anyway. All you can do is ask for a new hearing (I am not sure of the specific process, however).
Now...here's another question. Not showing up to court thats my fault okay. - How am suppose to follow a restraining order if I don't know what the restraining order issues. 100 Yards? 200 Yards? Email/Mail contact? etc.
Before you can be charged with violating the order, proof of service of the final order must be made. If there is no valid service, no crime for the violation can ensue. So, if you were not in court, you will have to be served again with the final order in order to be held to account.