BMW Of Tigard

I purchased a supposedly certified 550I from Kuni BMW with clean car fax report. Since then, it's been nothing but nightmare. after purchase, I came to find out that the car has had previous body work. So much for car fax report accuracy. So far, I have taken the car in at least four times for major electrical problem in which the battery gets drained and needs jump start, and each time I had to leave my car at the dealership for 2-3 weeks. I recently decided to get all the service record from them and realized that by mistake they also gave me the report containing internal memos regarding the customer complaints and their response to the complaint. In one of those reports the mechanic respond to my complaint regarding the electrical problem is "Bull Crap". which happen to be the date they blamed the battery for the cause of the problem and made me spend $400 to replace it. Within a couple weeks I had to take the car back in for the same problem. This is utterly disgusting and presence lack of integrity and competence on their part. I brought this issue up with the service manager and it has been months, and I am still waiting for some kind of explanation or apology.