You will most likely will have to go to court to show cause for why you didn't complete the community service. At that point the judge may give you detention days or a fin in lieu of the community service, and may add additional penalties. I would contact the court an see if they will let you complete your community service, or if you have to show up in court. You don't want to get yourself in to more trouble.
It also depends on the Judge, prosecutor and numerous other factors.
This communication does not establish an attorney-client relationship. I cannot advise you fully or appropriately without all the details of your case. Please do not rely on the advice given here without further consultation. Feel free to call me at any time.
If you found this answer helpful, please click the Thumbs-Up tab at the bottom. You can also mark this as a Best Answer if you feel like I gave the best answer.
The state can file a petition based on the juvenile's failure to comply with the court order; if found guilty of violating the order (wheteher it was probation or supervision), the court can re-sentence the junvenile and impose any sentence that could have been imposed on the original charge. You should contact an attorney, preferably one experienced in juvenile delinquency matters.