"Buy Bulk and Save" a Lie you have to check?

Buy Bulk and Save is a lie at Woolworths. Recently they had coffee beans for 1kg at R289 with a bright sticker on it "Buy Bulk and Save" On the same day you could buy 500g of the same beans at R135, thus R270 for 1kg. The if you buy 2 you get 20% discount, thus 2 times 500g less 20% would cost you R216 for 1kg rather than the R289 if I bought the bulk 1kg. Do I have to check the truth of "Buy bulk and save" every time I see this special at Woolworths? This has now happened twice at Woolworths Atterbury Boulevard over the last 6 months, both times it was reported to the manager on duty. The manager took all my details on both occasions and not once did they come back to me. I am still waiting. So, if Woolworths puts a "Buy Bulk and Save" sticker on their products, Do not believe it, check first. This is unacceptable and false advertising. Not good for any trust relationship?