Branch refuses to sell based on the adverti*****t

2 weeks ago a subwoofer priced at R799 'per set' was advertised. I spoke to the Branch manager and she said it wasn't printed correctly. Today the same item it's is still marked as a 'set'. I wanted to purchase the item the way its advertised but the branch manager refused to give it for the price and the 'way' its advertised. She made a call to her boss who was willing to offer 20% which I refused. I am not happy with this at all. The pice you see is the price you pay. It's advertised as a 'set', not each. I have taken picture both today and 2 weeks ago of the price tag.