BMW Menlyn disappoint me

Hi.. I bought my BMW from BMW Menlyn on Nov 2018. Its a 2013 116i model and on the clock 98k. The car starts giving me problem within two months and Major problem came out as 'Drive train' issue. I went to Joburg City BMW and they quoted R32k for fixing the issue. Then I went back to Menlyn BMW and after some some arguments they accepted the car and fix the issue. Once I got the delivery everything was fine but suddenly I found that the Auto Start/Stop functionality is not working any more, more over if I drive the car for long distance (~ 100-150km) the AC stops working suddenly. Also when the car running a long distance it gives sudden jerking which is very annoying and dangerous. Now BMW Menlyn don't want to fix the issues. I am not sure if its an accidental car, I am really disappointed with the BMW cars as its is giving me trouble from beginning and will never go for BMW again.