Online Promotion false advertising

I bought Olay Regenirist promotion products online, Buy 1 Get 1 free. I never received my free product. Clicks excuse is that I should have added an extra one to my cart to qualify for the free one & then I would have received my free product. Nowhere did it tell you to do this. This is false advertising. They are not prepared to give me the free product, they tell me to return the product if I am not satisfied.