Terrible customer service at thrifty RANDBURG

Appaling customer service from Thrifty in Randburg. They charged me 200 rand of refueling fees when i bought the car back with a FULL tank. I even showed the branch manager Leanne the slip from Engen prooving i filled up down the road from the depot. They assume i **** and don't want to help me at all. The branch manager suggested I send an email but only once I calm down whenI wasn't rude at all.