What Risk? Make me stranded for hour's without a car.

I rent a car from Budget i extended the agreement and was told to come in and change the car because i did have it for 3 weeks. I book the exchange car and was told to collect the car at a time. When i went i was told i can't have a car because im a high risk! I didn't go with anyone and was stranded. When i ask what high risk they told me to call on Monday. No i was stranded and they didnt pay my deposit. If i was a risk or there was a investigation why didn't they call me or tell me the time i did call to rebook the car. They always takes big deposits and you dont even get 1/2 back.