Terrible service

I am very disappointed by the service that I received at Westgate VW, my car is still under warrant and it started to misfire then I took it VW at Westgate hoping that that help me or Atleast identify the problem that makes it to misfire, worse response they told me that they can't see anything wrong, they told me that it might be the clutch that causes that, they told me that they have tested it and it's no longer misfiring, then drove it for few days it started doing the same thing, I lost hope because that taking the car the VW as the car is VW maybe they will fix it because it's their brand, unfortunately I ddnt get help, I am very disappointed, this simply mean that they ddnt bother to open and check the car, because it doesn't make sense that the car has fault but they say everything is fine. Do they want me to take my car to the street mechanic while it's still on warranty? These guys seem to be stingy when the service is free for the customer, if I went there telling them that IL pay cash, they should have fixed it perfectly. Just imagine they wanted to fix the clutch while i wasn't there for clutch because clutch is not covered on warranty, its cash. I rate them ZERO FOR THAT TERRIBLE SERVICE.