Dissatisfied with the service rendered

I am disappointed with the service received from VW Stridjom park, I took my car for the repairs on Wednesday to date the car is not repaired. I use the car for work purposes , to my surprise they are telling me that the car will only be fixed on Monday as they are waiting on a part to be replaced. I then requested a courtesy car and they are telling me that all the cars are out. How on earth am I suppose to get to work with , given the fact that it's taken for something that they failed to pick up initially when the car was with them for the repairs. They are inconveniencing me and I might lose my job because of this. Can you please me ASAP