Misleading advertising and bad customer service

Bought a BMW 316i 9 days ago from Silvertlake branch drove it home the same day and the following day I noticed that it was overheating and its cooling system is faulty. I would drive 10 minutes and then notice the temperature gauge increases to 120 degrees celsius. Contacted my sale person to tell him about it and he logged a query/complaint on my behalf. My mechanic looked at it and decided that I do the cooling system overhaul and hence I went to the BMW franchise to do a quotation for parts, which i subsequently sent to my sales agent. Three days later I got a call from their customer service lady who was so rude and didn't even understand anything about cars. She didn't help me with anything except give attitude, but referred me to someone else, who hasn't even contacted me even once, a week later. Currently, am stuck with overheating car that was tagged with GOLD rating and was advertised as having no issues whatsoever. Clearly this was false marketing and hence deliberately misleading so they make a sale. This is not the first time this is happening to me but I thought they have changed only to be burnt again. Am stuck with the case number 53757 that doesn't mean anything at all. I have not even received the roadworthy certificated they advertise the car that encouraged me to buy the car, if at all it exists. I would definitely won't recommend WBC Silverlake to anyone.... It would be like flushing money down the toilet. What a shame. Hope they contact me and sort this out as am willing to do whatever it takes to get justice.