Extremely Poor Service - 21000km still no parts!

I took my car to Ssangyong in Boksburg for its 80 000km service. The technician recommended that the CV's be replaced as they were faulty/worn. They said that they would order the parts and let me know when I could bring in the vehicle for the CV's to be fitted. I have since taken it for it's 90 000km service and complained at the branch more than 3 times and it has still not been done. My car is sitting at 101 000km now and is about to run out of the warranty plan( I assume this is the modus operandi) so that they do not have to pay for it. This is completely and utterly unacceptable. These crooks should be closed down.