Disgusting Customer service

I'm dissapointed, angry by the way my dispute is currently being handled. I'm driving a diesel car and petrol was dispensed into my diesel car, this happened at Total WF Nkomo also known as Total Hansa Auto Service in Pretoria Gauteng . The manager (Avi) promised to fix my car, when I fetched my car it was in a worse condition than before the incident happened. He didn't even have the disancy to be present when i fetched my car which can only mean one thing that he knew that my car was not properly fixed. A document was left at the filling station for me to sign which I didn't sign and i also left the car at the filling station. When called Avi, he told me he fixed the car as per the problem and there's nothing more he can do. I humbly request Total to intervene and resolve this matter. My number is ***