Legal Question in Criminal Law in California

If it was a lawful arrest [the officer had probable cause to think that you had committed a crime--normally difficult to disprove], then as you could not move your car it was not improper to tow it. Likewise, requiring your paying a bail bond or putting all the money up yourself is reasonable. That the DA then decides not to prosecute because there is not enough evidence to show you committed a crime [higher standard of beyond a reasonable doubt] does not change the lawfulness of the prior acts, as the legal standards of proof are different. Also, if the arrest, bail. and tow were all found improper if the DA did not press charges, the DA would be encouraged in more cases to press charges in order to protect the police and public entity, and society should not want that to happen. It is frustrating to you, but it is better than the DA pressing charges

You are not going to get the money back. You would only get your own money back if you posted your own money for bail, rather than use a bail bondsman. The portion you paid was most likely nonrefundable, and this language is in your bail bond contract.