Did you file against them? If you didn't give any statement and file a police report for the attack against you then your credibility might be an issue should you even proceed to filing a lawsuit for defamation. I doubt any attorney will take a defamation lawsuit on contingency and will require you to finance the lawsuit. Chances are slim you'll be able to get your money back or even be awarded a sum commensurate with the damage. It's extremely frustrating and something that seems very unfair. But in this instance, even if a district attorney would choose to go after these people for filing a false police report, there would need to be sufficient evidence to pursue. I don't know that this case for defamation would be a winner and whether a prosecutor might feel there is enough evidence to proceed with criminal charges for filing a false police report.