OK Furniture changing quotation price with in minutes

I had a very bad customer experience at OK Furniture Bougainville Shopping Centre in Pretoria. I find this very very unacceptable to do this to customers.

I visit OK Furniture's Sunday to buy me a bed. I was given a quotation by OK sales person for a queen size Sealy bed. The bed was on special for R5000 and I agree to buy the bed immediately. I wanted to pay with my card and Sales person informed that card machine is not working. I went to withdraw R5000 out of my account. I return to OK and while waiting to pay, the bed price changed to R6700 on the system. I called the Manager and he informed that bed is part of a special and I have to take a phone with the bed after spending more then 2 hours waiting and running around to buy this bed. I asked the Manager where is the phone story coming in now and they just refuse to sell the bed on the quote given. This failed transaction left me frustrated and very unhappy with the service. You can never give a quote and change the pricing of an item with in minutes. I need urgent assistance on this issue.