Car Faults

I bought my car at GWM Midrand a kia picanto striker 2010 model. The saleman was Shaun Young and upon getting this car i discovered that the car , though having said to have passed the roadworthy test at Dekra Midrand had actually not passed as stated on the report. My insurance requested that i take my car in for a check , of which i did at Tyger Wheel Midrand , and they picked that my tyres were worn out , yet the roadworthy test had passed the car with flying colours. Which i then complained about to the manager Shaun Sewpal as i had to replace the tyres. They refunded me the money for my tyres and that i was pleased with as they took ownership for it. I have had this car for 3 weeks and lately it has been having a squeaky sound as i drive , so like any other driver i took it in to be checked, and to my surprise my shock mountain, shocks and brake pads were worn out, Upon addressing this with my sales guy Shaun Young, he referred me to his boss Shaun Sewpal who then bluntly refused to take any ownership for it , even having sent him the report from KwikFit Centurion where i had the car checked. I do not understand how the car passed roadworthy with all these faults.Not Pleased