VW Tcross defects on spark plugs

Good day

I have been having an issue with my VW Tcross that i purchased in 2022 from the VW in Umhlanga. In early 2023, i started noticing a jerking effect when accelerating or on an incline, eventually the engine warning light switched on and i took it to VW Ballito to get it diagnosed. My service consultant was Fiaraz and he indicated that after the assessment it was in fact the spark plugs that were worn out. I was shocked when i heard that i had to pay for the replacement of the plugs yet my car was new and under warranty, i was told that this was my fault cause of the petrol i was filling in the car which i have no control over.

I was told that i had to pay an amount of R2800 and this was in October 2023 when these plugs were replaced and now again this is occurring, six months later i have to replace them again at my cost. I believe that this is a VW defect on the car that VW SA does not want to own up to. We need to have this resolved because it is now a displeasure to own a VW and there is absolutely no peace of mind. I need not to pay for a VW defect for a new car which is under warranty. Make it make sense