Possible Collusion with Dealers who mess up

I have purchased a vehicle from Autoteam East Rand. To cut a long story short, Dealership messed up with the price, tried to do a quick one, then got caught. I was then offered the vehicle at cost, which I accepted. However, I feel that this dealership, together with Wesbank has been colluding to keep the interest rate high in order for me to lose interest in the vehicle and the case would be considered closed.

My issue with FNB / Wesbank is that when I phoned them to have a Face-to-Face in a branch, they said this was possible and can be done at any FNB branch. When I got to the Boksburg Branch, nobody would assist me and insisted I do it online. Then I did it online in the hope that at least I will get to speak to someone. But instead, I was just referred back to the dealer. This means that I could not state my case at all as nobody at FNB / Wesbank is willing to assist. And the deal I am asking for is not far off the deal that was offered, so this is just more proof that there is collusion between the dealer and FNB / Wesbank. Taking into account how unfriendly the finance lady is at the dealership, and how she treats the staff members there, this does not surprise me at all. I want someone to call me and tell me why the interest rate is charged at the astronomical rate it is, especially when my credit record is impeccable and affordability was clearly proved.