Poor quality fuel

<p>I always fill fuel at caltex and stopped to fill at the caltex next to berea centre in durban.I filled R 450 petrol in my car which is only 2 years old and 50 000 mileage.Ever since I filled the fuel my car has been giving problems.It keeps stalling and vibrating when I go past the 4th gear.I took it to a mechanic and he said it's the fuel.I had to use engine cleaner.</p>