Discount

Today I went to woolworths in Northgate. The one lady on the floor told me that I will get 20% off if i buy any 2 products in the women's department. I didn't get the discount. So i went to the customer care desk they then told me its only certain items. But surely if one of their staff told me any tgen I'm entitled to the discount? They then just left and let me stand there for nothing. Extremely bad service