Couple questions,
Transmission failure would fall under collision insurance which would normally be covered by your credit card. Are you saying that you paid $2700?
How did you come to choose this rental company?

This is a topic frequently discussed on this forum. Final analysis? Just as RonDon stated, there are reputable, reliable rental car companies named by many of us on TTOL.
Unfortunately, there are some that aren't trustworthy. That, in my opinion, doesn't make the island unfriendly, just that unethical company.