Unsatisfactory service

I am extremely not happy with the service at their Linden-randburg branch. I took my car there for a service but it came back damaged I had to take it back for them to fix for that oil lick, subsequent to that the car / engines shakes. Why is my car now having all these issues after I took it to them, so with this issue I am suspecting they didn’t tighten something. It is so frustrating because to take a car back that’s another money to spend on petrol and it’s also time .