Nissan SA Warrranty claim refused

I Was very happy when i bought my navara in September 2013. But soon I experienced dust comming in the cab so badly that every night when i blow my nose out on a tissue it was red with dust that accumulated in the navara cab. I then told the BB nissan group dealer in Silverton of my problem after haveing the vehicle there 3 times all they have to tell me not to have dust is i have to drive with the fan on inside the cab to force a pressure from inside the cab. I then told them that i have done it and tried it but they still treated me as if a was an idiot that dont know nothing. Then later on my vehicle had a problem with the font diff in 2014, then contacted Nissan SA and told them, i then had the vehicle in at BB nissan Sinoville. Thank you Nissan you replaced the whole front diff but i had to wait 3 months for the vehicle i got it back the first week in December 2014. At that same i also complained a 4th time about the dust, stil not done. Then the back diff broke, the refuse to fix it because there is water in the diff. I dont drive in water or river apart from the rain or pothole water. The dam thing is under warranty the refuse to repair. Pay me my money back and keep yours