Unjust and waste of time

I wanted to purchase a used Honda Civic from Mazda Edenvale. I had a trade-in and provided ALL the necessary information to Garth in order to determine a trade-in value.

Playing with open cards, every pro and con of my trade-in was disclosed; including pictures. I was given a figure which I had accepted (and yes I know it was still subject to inspection), I was then asked to bring the car in for a physical inspection.

Upon inspection, Deena the manager advised that all seems to be in order except for one defect, which I agreed to repair. Later Deena had "re-evaluated the offer" and dropped the trade-in amount by a whopping R15000 (30%). No reason was given.

I requested a relook from Garth, considering the explicit information and pics I provided and the actual vehicle were no different! Still no reason provided or leeway.

An adjustment would of 5-10% would have been acceptable for unseen defects.

Unfair to say the least and a total waste of my time.