Audi A4 shudder denial

I took my Audi A4 2019 into Audi Port Elizabeth in August 2020 because the car started shuddering at speed. I replaced the tyres as it was suggested that one of the tyres might have been damaged. It didn’t help the issue and Audi blamed GoodYear who then replaced the tyres. The issue still wasn’t solved. I went back to Audi Port Elizabeth and they started measuring parts and kept denying that there was something wrong. I eventually took to car to Steering and CV Solutions who showed me a part under the vehicle which had too much play. Another auto shop owner also came and looked and confirmed the same. I took this back to Audi PE who still insisted that it wasn’t the car. Eventually went and got another set of tyres from another brand and again it didn’t solve the problem. So back I went to Audi and they started measuring again. This time they came back and stated that there was an issue with the CV joint going into the gearbox. They ordered the part but when it eventually came after 3 weeks they couldn’t install the part for some or other reason. They then got hold of Audi SA who sent their tech info o come drive the car who then agreed that there was something wrong with the gearbox. A whole new gearbox was ordered which took 2 months to get here, all the time while my car is standing on a lift at Audi Port Elizabeth. I eventually got the car back and it drove like it used to before the shudder but that was short lived as it started shuddering again the next day. So, Audi A4 not fixed. I went back to Audi Port Elizabeth and they told me that they are giving up and they’re escalating it to the factory. Yesterday the tech from the factory came, apparently drove the car but could not feel anything. I just received a call from Audi SA informing me that the case is closed because the dealership and Audi’s Factory couldn’t feel anything wrong and that the car was functional. This is the most pathetic organisation I have ever come across. I have owned 4 Audis and have had years of problems with all of them. I will never buy one or suggest the brand to anyone! Audi SA…you are a joke!!!