They should have given you a notice of forfeiture--you need to follow the instructions on that paper, however it's best to have an attorney so you ensure you get the money back and don't walk yourself back into any criminal case.
How long ago was this? The law is very specific in terms of time limitations for forfeitures. You need to speak attorneys who practice in this area. Many reputable attorneys offer a free consultation. I suggest contacting a few. Good luck.
for Fairness / for Your Freedom because sometimes good people get into bad situations.
The response above is not intended as legal advice since it’s impracticable to provide thorough, accurate advice based upon the query without additional details. It is highly recommended that one should seek advice from a criminal defense attorney licensed in your jurisdiction by setting up a confidential meeting. Moreover, this response does not constitute the creation of an attorney-client relationship since this message is not a confidential communication because it was posted on a public website, thereby publicly disclosing the information, which is another reason to setup a confidential meeting with an attorney.