Pensioner's discount at Makro is a farce

Makro advertises that they give pensioner's discount on Tuesdays. I asked the salesperson specifically about the discount of 10% as advertised and he confirmed that a 10% discount would be applicable to the product that I want to buy. I then commiitted to the sale and presented my Makro card as well as my credit card. Only then he says the discount is only 2,5% and not 10%.