Thrifty Car Rental King Shaka Airport Appalling Service

I made a booking yesterday through Rent a Vehicle in Cape Town and it confirmed. I arrived this morning before 10h00 to pick up the vehicle at King Shaka Airport but I was told I failed the Credit checks due to some irregularity. I was referred to Ridwaan who is the Branch Manager. He just ignored me when I walked into his office to enquiry and got busy with a phone call. I then requested my Credit Report from Transunion and there are no judgments against my name. I am really puzzled as to why I was inconvenienced and had to go to another Car Rental Company to hire the vehicle.