Unreliable VW Car

After taking my VW Golf 7 for a 45000 km service in November 2018, at 48500 km an engine oil light came on and I took the car back at Barons Edwin Swales where I had done a service. I was told to buy the engine oil and top up every after 1000 km the car travels. I've always driven VW cars old and latest models but I never had to top up the car engine with oil other than from an oil service change. What has changed?