Unhappy customer

I am very much disgruntled with Tempest Rental Company ( Cape Town branch ), In June I rented a vehicle with them and when I got there to collect I requested a different vehicle that was on the same group as the one I rented because I was not satisfied with the one they gave me and it had a lot of cosmetic scratches which I didn't feel comfortable with it, only to be told that it's the only vehicle they had taken out at that moment but I could see an available same vehicle group there only to be told it was not taken out for that day. I felt very undermined because at the end of the day I'm not getting the vehicle free of charge I would be paying. But since I was rushing somewhere I had no choice but to take the vehicle.

After returning the vehicle they requested that I rate my experience and I noted everything down then I was promised and upgrade on my next rental. Now it's time for my rental I informed them about the promised upgrade and they are coming up with a lot of stories that do not make sense. I feel they are not giving excellent customer service as a rental company should because they deal with people on a daily basis. Their level of client service is very poor and I would never recommend them to anyone in future.