Bad Prices at Tile Africa

We bought tiles and adhesive from Tile Africa on friday, when we went to Builders Warehouse on Sunday for something else we found that there was massive prize differences...for example the adhesive alone was R90 cheaper at Builders for the same product. When we returned the stuff to Tile Africa today, the prizes went up again...the adhesive was now R120 more!!!!???? We got a cold reception from....I think he's the manager...telling us they only receive the prizes from somewhere...headoffice??? they are not involved in prizing...I was so disappointed seeing that we always bought tiles and stuff there, almost our whole house was done from there store...I guess they just don't care about loosing our business