Bad Service

I took my car for service on the 3rd of March to VW Polokwane and the service was very bad. The service Adviser by the name of Stephanie was friendly and all that but my problem is that I was charged for major service for an amount of R5700 and even today I've never received an invoice for it because she told me that the cashier already left and just swiped my card on their speed point and it was after hours and I'm not sure if that speed point belong to VW, then she said I will receive it via email .The sad part is that the technician ****ed up my car because when I got home I've realized that it was not in the same state that it was before. They booked me again on the 11th to fix their mess but told me that I have to pay extra R1100 and I agreed. This time around I was clever enough to ask the cashier before she leave the premises that, "how am I going to pay since you are leaving? She rep**** by saying," no Service Adviser told me that there's still a customer that need to pay. That's when I realized that this doesn't make sense and I decided to leave without paying and today no one called me to ask why did I leave without paying. I am very angry because when I left that day Stephanie told me that she knows I'm still going to come back and it is true because the car is now giving me problems.