“No refund policy”

I walked into Shesha “The glen” to purchase a sneaker for my son, he generally wears a size 13/1 and unfortunately the sneaker I got was small, went back to the store to be told there’s no refund, I don’t have a problem with the staff, I do have a problem with a policy I was not made aware of prior to a purchase. Quiet unfair because they don’t have sizes, none of the other stores do, so I’m forced to buy a different sneaker. There definitely has to be a law against this.