Transmission Not Engage problems of the 2007 Volkswagen GTI

I was at an intersection with a traffic light, waiting to turn left. As soon as there was a safe and reasonable gap between oncoming cars, I hit the gas at approximately 1/4 throttle to make the turn. However, the car moved for a bit and then it felt like the transmission was not engaged anymore. The car was basically moving by momentum and not by engine power. I noticed that the engine seems to be revving freely, as there is no correlation between my throttle input and the movement of the car. In fact, when I noticed that the car was not moving by engine power, I instinctively put more throttle to more than 1/2. It made no difference and that was how I knew that the transmission was not engaged. If it was traction control, the engine would not rev since traction control would cut the fuel. Hence, it is most likely the transmission, specifically, the dsg transmission. My car coasted to safety without any incident, and a few seconds later, the car went back to normal. I have had this experience several times before and it scared me every time because I could have easily been hit by the oncoming traffic, if the vehicle does not see me or cannot stop in time. I mentioned this to the dealer service the first time it happened, but they said they cannot replicate it and thus, they can't and won't do anything. But, for me, it is a serious safety issue, whether they can replicate it or not. I just want the Volkswagen of America to take responsibility for their unreliable/ faulty transmission.