"The stores are not tall."
Translation:Az üzletek nem magasak.
Being English and not American the only time I would refer to "stores" would be department stores "áruházak" otherwise I would always use shop/s üzletek/boltok.
With reference to the word "tall" department stores would spring to mind and not shops
I wrote - Az uzletek em magasak, apparently wrong word. I should have used boltok?
Az üzletek nem magasak. - that is also correct. Did you reported?
It is a correct sentence with a slightly different emphasis. It could be accepted.