Bad service

My car was due for service on the 2nd of July, my sister took it in to VW Hatf**** braamfontein likewise. After my sister dropped the car off I then received a call from a gentle by the name of Jamiel, who told me what needed to be done. And he told me that I would be charged R15000, I told him to just service my car as agreed as I did not budget for all those extra things he had mentioned. My sister fetched the car and on the 3rd of July she told me that there was something that was bothering her, she told me that when she drives the car it’s no longer the same and it struggles to pick up speed and it had this strange vibration, like literally we would just start vibrating while sitting in the car. I then called VW on Wednesday morning, the call was immediately transferred to the service technician Jamiel, I explained the whole story and this guy sounded like he knew something it was as if he had done something to the car deliberately so that I could come back and most probably because I’m a woman, I would think that there was something wrong with my car which they needed to fix which obviously meant more money. When my sister took the car in on Thursday she didn’t get an explaination as to what had happened to the car the guy just said the car is fine, well that’s after they had fixed it of course. This technician insisted that it’s because VW has new parts and they have changed, what on earth is he talking about? Worst part they didn’t even call to apologize after this whole incident, as an individual who works with clients, I certainly know that this is not the way you treat your clients, clients who are bringing an income to the business. After this I never want to bring my car for service at VW Hatfield, you guys have disappointed me.