I had hired a so called legitimate collection agency to collect debts for my small business. This has been almost a year ago. Since then I have not received a phone call or money from them. I have tried cailling, and the number is out of service.
If they just left you hanging with no communication they may be out of business. You might contact your Louisiana Secretary of State as many states have registration systems for collection agencies. If they are out of business, hopefully they were working on contingency and you can start over with another company.
If they actually collected money and didn't tell you, then that's another story. In that case, you'd want to talk to the district attorney, attorney general, and ftc to try and get someone looking at the matter (but don't jump to conclusions, because that's a serious allegation). Good luck.