First, we should all thank the OP for posting a warning. It really helps to know what to watch out for.
A long time ago I learned that the local brand name car rental companies are not affiliated with the US companies. In my case, I was quoted a good price and when we arrived the company had no cars. Had to go to another company and paid through the nose. In fairness to Hertz/USA, they rebated the difference I paid only because their good name was used (or abused) by a SXM company.