Misrepresentation of promotional goods

I bought a McFlurry at McDonald's Santon and i loved the ice cream it had all the flavors the chocolate syrup and Oreo bits ....PERFECT!!!! . I'm not a ice cream ***** but i enjoyed that . I went the next weekend hoping to get the same McFlurry at Evaton McDonalds and i had to wait 40 min to get my McFlurry only to get it and find a cup full of Ice cream with Oreo biscuit crumbs on top . It makes me wonder why would McDonalds sell the same product advertised at one place but give less ingredients in another ? I'm very disappointed . What I bought at Evaton McDonalds was nothing like your advert .