Bad service

I received a bad service from one of petrol attendant there even the manager can't handle or solve the situation,my car has air lock and he decide to leave the car go to the next one and I told him about airlock and all the petrol gone and I must pay full amount because he claims its a mistake and its not for the first time,and he told me he is not gonna help me anymore and I use the garage almost every second dato put a petrol there,