Long duration of repairs

I have handed in my car for repairs on the 8 of February 2016. They first told me that my car will be given back to me on the 17th of February. On the 12 of February they sent me an sms that my car will only be given back to me on the 29th. That is already an additional 12 days i have to wait for my care due to parts. Today, the 23rd of February they yet again sent me an sms that my car will only be ready on the 4 of March. I now have to wait for 24 days for my car due their bad planning. I need a car for work every day . I have to use my own vehicle to visit clients. I will not wait a day longer due to their bad planning. I live on my own and now have to be dependent on more people. I cannot afford to wait a day longer