Looking for some advice here. Last weekend my 2019 Grand Sport's, with 2600 miles, information cluster lit up with a stability yellow light and then a check engine light. A message came up Service Stabilitrak / Service Rear Axle. The engine was running rough and at highway speed and developed a severe vibration in the chassis. I dropped the car off at my local Chevrolet Dealership. As of yet they haven't been unable to identify the problem. I'll give them another week but I guess my question is if they can't get it fixed what are my options?