Gross incompetence, shallow and lack any knowledge - 4 months to fix a sensor

My car was fixed by Renew-It Randburg. They did the job well and were finished in February 2018. However, they did not resolve one problem, the parking sensors.

I told them a week later, after I had collected my car that the sensors were faulty and they said I should come into the office. They didn't fix anything. Two weeks later, the lady I was dealing with left.

From February to May, I have been pushed from pillar to post. I visited them three times but to no avail. I call them and they say 'give me your car registration and we will get back to you' and that is the end.

They have proved to be *********** after having done a good job.

How long does it take to fix sensors, really?