poor explanation presales

I ordered this item for my 5 year old son. One comment stated that the size was 5-6 years.
However, the one I got is size 8-10 years! So not terrible, way too big for my boy. I planned this for Christmas, so he'll have to throw myself into the seam before the big day, otherwise, it will be under the tree disappointment when he wants to dress up!
It is therefore necessary to order "blind" without knowing the size that we will receive. Level sales and explanation is zero!