Shell Scotch Service on Republic

i asked the assistant to fill R100 fuel which he didn't do because the car didn't fill. the manager assured me that my fuel gage would rise as i drive which it didn't so i then took my car to Kia to have them check everything. they confirmed that my car was fine and that there wasn't any fuel poured which is frustrating because i had paid for it before the guy "filled" and my car is still running on reserve tank. the garage i am talking about is Scotch Corner service station on Republic in Randburg. Terrible service.