We buy cars germiston branch

I bought a car on Friday, dekra reports and sales person states that the car is a diesel car .I poured a diesel a day after as indicated .turned out the car is petrol.i called the germiston branch where I bought the car and they said they cannot help me in any way .The car is stuck now a day after I bought it .I dnt know what I am supposed to do with the car now. We buy cars germiston branch the manager talked to me like I'm his child