Not sure how they did it, and part of the fault is on me for not being more careful. We rented from the dollar/thrify at Iberostar for a day in April, getting the full coverage insurance, but somehow in the exchange of paper work, I didn't get my credit card back. (And you can bet in the future I am going to check every piece of paper under credit receipt since they hand rub the number) But Charges ended up showing on my credit card beginning the day before our rental to weeks afterward, well after our return home. Most of them are listed for a pedro garz, with a gncsn before the name, although one was for fuel. (after reading other posts, we excahanged cash and paid for fuel with pesos, and being wary of the surchage issue. Fortunately that is something that can be fixed by cancelling the card and reporting as fraud.
The other mini rip off that has now occured twice, once in Cozumel and the other in Playa del Carmen, is that they inflate the exchange rate. So they quote 86 dollars, but then put down 86x13.5 exchange rate to give you a rediculously high peso amount. And they refuse to allow you to pay in cash, even after you have brought the car back and it checks out OK. When we go back to Cozumel, I guess we'll try the small private company in hopes of not getting ripped off.