Complaint of faulty vehicle and bad service

I bought my car in January 2018 at Active auto car dealership,a blue BMW 116i. First month already it gave me a problem. I had to take it in their workshop as it still was under warranty. Since then its been in and out of their workshop every month. The turbo coolant pump was replaced as it was blocked,the water pump was replaced it was leaking,the water bottle was replaced as the mouth was damaged and had a crack and etc. It has been to the workshop more than 7 times since i bought it in Jan. Everytime they fix it 2 or 3 days after i would have the same problem signal coming up. Currently its been now 14 days its at the workshop. When i call for an update they tell me i need to pay for the water bottle as it is not under warranty. The sensor is not right,the bottle my car had has no guarantee. I told them how can i pay for the bottle if it was bought by them in March as the 1 that was originaly there was faulty. I took the car to them to replace the bottle. I will not pay for a faulty bottle they purchased initialy. I raised my unhappiness of their service and car problems since the first month and this goes unheard. I told them my car has been to their workshop more than 7 times since i bought it in Jan til now. They tell me that my car has only been to their workshop 3 times as per their jobcards,which this is a total lie. I can ask Altech Netstar tracker to send me a trip report of when,where and how many days that my car has been to their workshop address as evidence. Now if i dont call for an update,they dont call. The mechanic told me my car is not leaking(coolant). I told him its not possible because every 4 days i pour water as the levels drop. Previously when i asked to see the branch manager regards the faulty car. I was told to make an appointment. A customer needs to be make an appointment because of a faulty car she purchased by them. This is not right, i am their customer. I am tired of this car being in and out every month to the workshop since February,pouring water in the bottle every 4 days. It took them 3 months to settle the account after my trade in with them, and this is after me making noise. The faults continue... please please help.