Bad Service from Builders Rivonia/Online

I checked online for a vacuum cleaner and found one at the Rivonia store. Stock available showed 4, so I went to the store, but was told that all the remaining stock was faulty. I offered to purchase the Demo unit but was told that they're not allowed to sell it. The person assisting me took my details and promised to call when more stock arrived which was supposed to be that same day.

I decided to order online so that I didn't miss out on the special. I kept calling to check if stock had arrived, and was constantly told that they call center could not get a hold of anyone at the store (thrice). Eventually I was told that I can collect as all is in order.

I collected and lo and behold, I was given the Demo unit. When I called the Call Center, I was told that it wouldn't be possible for them to collect the demo from me. This was a terrible demonstration of customer service by Builders. Please rectify!