Generally, proper service of process on a person is either handing it to them or handing it to an adult at their residence. There are exceptions and some jurisdictions allow substituted service. If you were not porperly served, you cannot be found in contempt of court for failure to appear. However, you need to contact a local attorney in your area to determine if the service to your boyfriend's home, was proper service on you.
In California, a subpoena is not deemed effectively served unless it is handed to the person directly. Subpoenas sent via mail are only deemed served IF the person contacts the party serving them and identifies themselves by name and DOB or driver's license number.
The circumstances you described, the prosecutor cannot establish proper service of the subpoena.