Warranty claim not honoured and pathetic service levels

4 years into ownership of a NP200 the aircon started giving issues. Took to Algoa Nissan only to be told the aircon needed to be regassed. They could not do it in house to they sent the vehicle to a nearby shop who regassed and the aircon worked for a several months. The aircon stopped working and I took it to be regassed again. A few months later the aircon stopped working again so I took the vehicle to Algoa Nissan. They kept the vehicle overnight while doing a routine service and told me they had regassed the vehicle in house and that I test the aircon. The next day the aircon stopped working again. I then left the vehicle with the dealership for 2 days and then get told the airocn evaporator unit is faulty and now I must pay R 12000 to fix as it is now out of warranty. This unit had been failing since the beginning of the issues WHILE UNDER WARRANTY. I raised my concern with Nissan South Africa and now after 6 weeks I still dont have any feedback. Each week a call saying they are still investigating. They are not interested sorting out the problem which should clearly be covered under warrantty. I even offered to pay a third of the cost as I had already been charged each time the aircon was regassed at R 900 each time. Will never buy a NISSAN again and Algoa Nissan are completed useless and "force" you to give good reviews.