Bad service from VW Westgate

I took in my car for repairs for EPC light and technician said it was a Turbo actuator but after replacing it EPC light is still showing, so they now said its the turbo and mind you the warranty now doesn't want to pay full for the turbo because they diagnosed it wrong. Been two weeks now waiting for the service lady to come back to me about the way forward. honestly bad service from VW Westgate