I baught a car Ready to go

I baught a car Ready to go. But, when I took it on the road, it had a shudder. I reported this the very next day, but am struggling for them to sort it out. This happened on 26 April 2026. I feel they not stepping up to the plate. It should have not passed the roadworthy. The test drive they take you on is around a block and this shudder only happens when you cruise between 40, 50 kmh. If you are accelerating it does not do it. The guys that sold me the car did a good job, but #WeBuyCars should not have had it as a ready to go. Therefore they should fix this problem.