Purchased a 2012 Nissan Navara with 80000ks for 21000 (including an interest of $37000) from Grantley Davis at Southport Car Sales. This car has had major faults including, severely worn steering rack, faulty transmission, and several motor issues. It has been returned to the car yard several times for repairs, which were not completed due to the stating that it was the manufacturers problem. Currently in the 10th month of the loan contract of 5 years, and have spent approx $3000 in repairs in that time. The car is currently not able to be used in any capacity due to failures. How do I go about this under Australian Consumer Law?