Disregarding their duties and making false promises

My car went in for repairs due to someone bumping my car at a shopping Centre. After a week of not having my car, I get it back with the aircon still not fixed. Phoned discovery 3 times to which they promised every time they will get it sorted as it was part of the original claim. Me phoning after them, wasting my time and airtime due to their incompetence and yet after trying numerous of times they have not done a single thing and neglected to sort it out as they promised they would.