Car Service Awareness

I took the car in for the first service (15000km) today 23 October 2019... I was initially quoted R2700 for a Polo sedan 2019... but they agreed to match a R1650 quote I got from VW Menlyn. When I was called to collect the car less than 3 hours after dropping the car off, it was washed and clean. But when I opened the bonnet I found that the oil filter wasn't changed as well as the oil. And that's basically the service that was meant to be performed. Had I not checked... I'd be driving a no serviced car for another 15000km... How many of us trust dealerships to make sure that we get the best service? What happened to quality controllers?