Car Serviced -Oil not changed

“I asked my son to take my car in for its first oil change. The vehicle is 1 year old T-Roc with 6200 km and requires an oil change at 15000 km or 1 year, whichever comes first. The staff at VW Waterfront said the oil change was not necessary and reset the display to say the oil change had been done. This would result in the car only getting its first service 2 years or 21200 km. I then took the car back to VW Waterfront and confronted them about why they reset the service intervals without changing the oil. This turned out to be a 2-hour argument. Only once I said I would pay for the oil change, and not have it as part of the first three-year plan included, did they agree to change the oil, my actions resulted in the service interval being correct for the life of the car. If I was not forceful, I would have been dismissed. I am concerned that VW Barons Waterfront may cut costs by saving on the services and parts. Are the filters being changed? Are the spark plugs being renewed? Oil, how old do they allow it to get, we as the customer have no way of knowing, either way, this is something you would not expect from a reputable dealership like VW Barons Waterfront, be warned.