Delivery date moves after they receive payment

We purchased bedroom suite for R29 000.00 and had to pay 50 % up front, they phoned us to confirm unit was complete and they can deliver on 31st of July 15, our house wasn't complete and we asked to move the date and we would confirm to which date once we know when the house is complete. On the 30th we got confirmation and decided to have the unit delivered on the 4th of Aug 15 at which time we were informed that we have to pay in full before they could deliver. Which we obliged. Once payment was done we received a call saying that the unit isn't ready and will only be ready on the 7th. This in my opinion is very poor business ethics.