In spite of all my phone calls, emails and snail mail letters, I still have not heard a thing from Thrifty.
But on the plus side, I did call customer service again and received some news that made me feel better. Apparently, they have mailed me a letter along with a refund check for the rental plus coupons for future rentals. They also contacted the owner of the Tampa franchise regarding my complaints.
Sometimes the mail to South Florida can be a bit slow so I'll cut them a little slack. It will be interesting to see what they say. Hopefully, it will not be a form letter. I'll post a follow-up once I hear from Thrifty.