Disgusting after sales service on brand new faulty aircon

I recently bought a brand new LG Aircon for my bedroom from Hirsches Dunkeld. Hirsches installation did the install which was good and professional. The Aircon is faulty. It cools but does not get cold enough. I went back to Hirsches a few days after installation to complain. It took a few days and several calls before they sent the installation team back to check the system. As far as they were concerned, it was perfect. Two days later I went back to Hirsches to complain again and was promised a call the next day. Two days went by with silence. I then called Strubens Valley and spoke to one of the mangers who arranged for another Aircon specialist to come and assess the unit. That took another two days. They established that the Aircon was filled with air, not gas. They bled the system and filled it with gas by alas, this has not solved the problem. I called and complained again three days ago and was promised a senior technician from LG would contact me and come and do an another assessment. Nothing. Not a word. The unit is clearly faulty. Hirsches don’t seem to have a customer service Center or complaints department that can handle issues. I am extremely frustrated and disappointed and don’t know where to turn. I will never shop at Hirsches again. Very poor service Hirches. I want a refund in terms of the CPA.