Very Slack Customer Service

My car, still under warranty, was booked in for a service as well as a critical technical fault (driver airbag malfunction) on a Tuesday. Upon collecting the serviced vehicle on the same day, I was informed that a part for the airbag had been ordered and I should return the next day to have it repaired, which I did. By Friday morning I was still waiting for my car. There was no clear communication to me during this time and it was only when I became angry and demanded to speak to management, that my situation was taken seriously. Unacceptable customer service. I have been a customer of theirs for many years...not any more.