Bad service and no feedback

I was referred by my colleague to Steve's for doing a service on my car. They were quite friendly to assist by offering a major service. Upon arrival for my appointment they were very friendly and I filled in the document. Then later the morning the told me that they do not want to touch the car cuz of the oil leak and do not want to do the service. Instead they will just change the oil filter which almost took the whole day. I did not mind the wait and the gentleman suggested that I should take the car to the agency (I took it to the agency and they said that there is no oil leak that they could detect). I was excited to get my car but driving it a couple of meters I noticed that the car drives bad then before. It stalls, cuts out etc. When I took the car to the agency they informed me that someone cut of my oxygen sensor. At first I did not understand and took it to a sensor specialist that supplies the original parts for my vehicle. <br> <br> The friendly gentleman told me when I pulled up that there is something wrong with my oxygen sensor and he could hear it before I even opened my bonnet. Upon opening my bonnet he showed me that my oxygen sensor (which is very expensive) was cut off