Fuel Injector problems of the 2010 Volkswagen Tiguan

(cylinder failing/injectors leaking) engine light came on and the dealer said it was bad gas in my tank to let the gas run out and to fill up somewhere else. Car didn't have much power and idling wasn't smooth. They also said that if I keep getting bad gas that it will damage the catalyst converter which I then replied check the gas receipts in the car since I only buy bp and mobile 93 octane not my fault that gas station might be selling bad gas. We do own another car an Audi with a turbo engine as well and we get gas at the same gas stations and we haven't had any problems. Weeks later the car wasn't running any better so I took it to another place for them to let me know why the light was on. Code meant cylinder 2 and 4 failing. Took it back to the dealer and they told me that they had to clean the fuel injectors on both of those cylinder that it was due to the gas and that it wasn't cover under the warranty which I told them again check all the receipts in the glove compartment for the type of gas that I have been putting in. Then he asked me if I drive it in the expressway which I said sometimes on the weekends and to take road trips 2 to 3 times per year. He mentioned something about city driving that the car needed to be driving at a higher speed which I then reply: it is not on the manual and this is my fourth vw turbo engine and never had this type of problems then he called me back and told me that it was the way the new engine were designed that they will take care of it which they did. I just hope this doesn't happens every 23k miles. It will be very expensive repairs not counting when cylinder 1 and 3 starts to fail.