thrifty car rental kept my deposit reading, Internet

I booked a van for 8.30am .On arrival we were left waiting for approx 1 hr ,When we dared to ask why the staff became abrupt and rude stating that their computers had crashed.Well that's not my fault so we took our buisness elsewhere ,

When we contacted customer services to have our deposit refunded we recieved a e-mail stating we left and did not fulfill their terms and conditions ? I replied stating ,No you were unable to provide a service so we took our buisness elsewhere and besides they had already acknowleged they had a system crash ,On the third reply they stated that ,the case had been reviewed again and we were at fault ??? Case closed and go see their regulator ! So the facts are if they are unable to provide a service the customer had to pay for it ? Shockingly poor attitude