Poor after service and not owning up

I am extremely disappointed in Rola Ford Caledon. My wife bought a Rav 4 at the dealership and upon viewing, I made the Salesperson aware of a dent which they promised to have fixed. Almost a month later, they still struggle to get hold of "the guy" that can fix it. How on earth, you are a national brand!! I also made the Salesperson aware of a sound that I hear when I drive - coming from the tyres. He got a 'senior person' from the workshop to drive with him a week after we bought the car. I am driving long distances every day and can pick up on stuff like that, but was told that there is nothing wrong and that I should not touch the tyre pressure - which I checked being at 1.6kpa. I only had an opportunity to go to a tyre place on Friday 27/7, and when I explained what I heard, they went straight to the tyres and advised that it is totally worn off on the inside. When I advised the salesman of this, i was first asked what the milage is on the car - I then knew thar they want to blame it on the milage travelled, which they did. I traveled about 2400 kms since I bought the car, so this means that a tyre's life span is about 5000km to be totally worn - if I look at their reason for not wanting to own up to this. According to the manager at the tyre centre, the tyres could not have been this worn from even 6 months drive and it should not have passed roadworthy. This raises more questions on how big companies like yourselves get vehicles through the roadworthy test. My point is that I reported this sound to him within the first week, and they conveniently did not hear it. It is easy to treat clients like this after the sale has been made - is the company to big to care about one client? If this is how they treat their clients, they may as well count me and my ring of friends and family out as future clients.