First and foremost, I am sorry to hear of this news, that your scooter was stolen. Scooters and mopeds are popular targets for thefts primarily because the ignition/starters can be defeated easily, and because since scooters/mopeds are not plated it is much more difficult for officers to identify them as stolen.
I am glad to hear that your scooter was recovered, but I wonder why the case was declined.
The role of the Fort Wayne Police Department is to recover that stolen scooter and identify and apprehend a suspect which it appears we did. When a case is declined, it is typically declined by the prosecutor's office and for a variety of reasons; you'll want to connect with that office for information on your case specifically. I imagine that since the individual was not prosecuted that there is no one to pursue for restitution. I see the dilemma here.
The only suggestion that I can make is to contact Victim's Assistance at 260 427-1205. I hope that they might have a solution for you.