Pump not removed

I stopped this morning to fill up fuel. I went into the convenience store, made a purchase and paid for my fuel. I showed the fuel attendant the slip and he said all was fine and he proveeded to assist another car. He did not remove the pump out of my var and as i drove off i hear people screaming at me, the pump itself snapped and i honestly am not even sure if he poured the whole amount of fuel. How does a petrol attendant forget to remove a pump from a car???