Dishonesty & Terrible Customer Service

On the 1st of February 2020 I loaded diesel in my car at Shell garage Dekema Rd &, Steenbras Rd, Germiston. My car stared to cut itself off every time I reach 80km/h. I know it's their diesel because in October after putting their diesel my car broke down. I took it for inspection I was told straightaway it was the diesel I've put in and I must change the filling station. I thought maybe that batch that was not okay, but now I know their diesel is a mess. Unfortunately when I went on Saturday, nobody knew how to drain the diesel, I was told to come back on monday the 03/02/2020. I went and their procedure did not work (draining with horse pipe). I was told to bring the car in the morning of Tuesday the 04/02/2020 their technician will drain it n replace it with a V Power diesel. I called later they said they are done but to my surprise. The gauge is exactly where I left it. I asked Thuli from Shell the lady I dropped my car with. She said she doesn't know because she was not around. Now I need to spend extra money to drain their water in my tank. I also lost my R500 buying diesel mixed with water, just like that