Thrifty loses a customer

i had the misfortune to rent a vehicle through Thrifty via Economy cars at the Cape Town international airport .The staff were not very helpful and the service even worse .I was overcharged by R1300 vs initial (accepted) quote and the first hour i had issues with the vehicle .It was replaced about 2 hours later with something that looked like a demolition derby survivor although mechanically sound i am being shunted between economy cars and thrifty regarding the rates charged , however Thrifty customer service is in need of a relook , maybe an exec should do a undercover test disappointed !Non returning consumer !