Tangawizi motors and Wesbank

Prior to buying a vehicle I got a R10k discount from the owner for a new Renault. Got a 9% interest rate from the bank. When I went to sign the papers it was raised to 9.5% and guess what, that 0.5% is exactly the R10k discount I got. I queried this but I got no response either from Tangawizi motors or Wesbank. Just bluntly refused to return my emails.