Poor / Unprofessional service – Aircon Installation

The provider does Aircon installations. Them not keeping to the initial arranged times to install my new aircon should have signalled what was coming - poor service. After installing the new Aircon, it worked whereafter it stopped generating cold air. It took various requests and broken promises to come back, just to refill gas. Two weeks later the aircon again stopped generating cold air. Attempts to get them to come back were met with more broken promises