Horrible Rental Desk Experience in Calgary

I am a frequent traveller, and this was the worst rental car front desk experience i have ever had. We arrived at 6 pm and I had reserved the car for 8 pm. Admittedly, this was my error. However, they told us we would have to wait until 8 pm before they could give us a car. There were other cars, but the cost was substantially more. We decided to wait since after lengthy discussions, it was only a 45 minute wait. At 8 pm, they gave us a higher priced car at the lower price, because our reserved car had still not been returned. It was not a car we were comfortable driving after dark in the pouring rain. They said their inflexibility was due to my pre-paying for the rental. I will never use Thrifty Rental car or pre-pay for a rental car again!!