Shell bunyan road benoni

I poured petrol for 250 and the was nothing in the tank. I drive a kwid 1.0 litre engine i shoild get 3 or 2 bars with that amount. But the shell petrol station in benoni bunyan road told me there is simething wrong with my gauge. I would like to expose them and stop everyone from pouring gas at the shell petrol station. They refuse to pay my money back and i want to take legal action.