When you say your former employer is reporting "false charges" do you mean that the company has a contract with the state and is billing the state for materials that are not used? If so, this likely violates the Florida False Claims Act. There are many attorneys in Florida who handle false claims cases. I cannot advise you about Florida Law but it is very similar to the Federal False Claims Act, and allows a whistleblower to recover 15 - 30% of the amount recovered for the government. These cases are also "qui tam" cases. If the overrcharges are at all substantial, you should be able to find many attorneys eager to take the case.
So you are looking for "False Claims Act" or "qui tam" attorney in Florida.