Economy Car Rentals review: Car booking ECF5F351 not honored due to overbooking and not reimbursed

I booked via economycarrentals.com website, for a car at SFO for 6 days, prepaying part of the rental and received voucher by email. When I arrived at the Thrifty/Dollar car rental counter after 11 hrs of flight, the car rental company did not have any cars. About 20-30 people were already in a waiting list and had been waiting over 2hr for a car. When I asked the manager to at least be reimbursed of my down payment - after he told me he couldn't help in any way - he explained I would have to get in touch with economycarrentals later on, where the booking initially took place, and they would handle it.

I contacted economycarrentals in writing right away, who replied the next day first saying they would check with provider, then later asked for my contract (even though I'd provided the booking reference), and the invoice (which I couldn't have had since no car was provided), then my boarding pass, and finally asking for a letter from the rental car manager. At no point was there any apology for a contract not honored by provider and the situation this put me into, but worse, no reimbursement, and on the contrary, a notice that I would get a penalty for not cancelling - completely disregarding this was a booking not honored by rental company due to their practice of overbooking, and not a cancellation on my part.