BMW quality or quantity cars

I drive a f30, 316i BMW 2015 model. The car started shaking and when I took it to BMW Clearwater the car was returned and they said the was nothing wrong with it. This problem started again a couple of days later. This time I could only move at a speed 20 and I call BMW Clearwater and they came to collect the vehicle for fixing. At the time the car was still on motor plan. After a month the same problem started again. Which leaves me wondering why? Did they do a temporary fix because they know my motor plan is ending or is BMW using **** parts when fixing it's cars. I'm not sure if I should put the blame with BMW Clearwater or BMW as a company. I have another car which is older and if I fix a problem it's fixed permanently. My question now is that is BMW a company that sell quality made cars or not.