Shell service station new ottery pathetic

I am extremely disgusted in the service I received from shell new ottery motors as there is a promotion running on the Coca Cola products it says buy any 2 flavors for R17.50c which I’ve taken a normal coke and a Coke Zero and the cashier says the promotion does not apply to those products. So please correct me if I’m wrong is this false advertising as the promotion on the brochure they advertise inside says buy ANY 2 Coca Cola products for R17,50c.. the staff was unhelpful and another customer agrees with me when I said that it says any 2