Defective Delonghi portable aircon units PACN125HP

Having lived with a Delonghi PACN125HP portable aircon since 2010 without problems, I decided in January 2015 to buy another unit from Hyperama. After using for a few days the machine began intermittent clicking when it reached a temperature of 20 degrees or lower. I registered my complaint with the store and the unit was given over to the Durban Delonghi service agents who could not locate the fault. Machine was returned to me after 2 months. Fault was not resolved. After numerous calls etc Hyperama agreed to swap out the unit. I was given a replacement unit from the service agents. Since using it this summer I noticed it too makes the same clicking noise. Worse, there is a constant rattling noise from inside the grill and the machine, when operating in normal 'aircon' setting, eventually switches itself to 'dehumidifier' after a few hours and then switches off automatically!! Spoke to Elias at Delonghi in December. He does not get back to me. Spoke to Hyperama in January who referred the matter to the service agents who yet again expect that I should bring it in again!! I have never been so appalled by Delonghi units. All I want is a machine that works like a new!