Poor service and not leaving their values cooperation and integrity

I had a terrible treatment at Engen Sky City garage where i had an argument with petrol attendants then the following day they decided that they wont help me filling up my car at their garage when i went back. They took my car number plate and said they wont help me anymore. The other thing is they keep on hiring new petrol attendant. It is critical for the manager to understand that the garage is important to the client but himself as well teach his subordinates towards treatment of customers. I am a resident of Sky City and had to fill my car with petrol by the nearest garage which was more than 7km away from my place. Is this garage not to help us as resident of sky city. How does this garage develop a good cooperation with residents of sky city especially its attendant. How can we improve communication and service levels of this garage with this arrogance. Sky City Engen use this method that it is always right no matter what as they are the boss they call the shorts.