Ipad not working

I purchased an Ipad that was going for a marked down price at your store in gateway. I purchased three of these Ipads as they were for my kids, they are only 5 yrs old so i didnt want to buy them expensive ones. I manged to get two working and they are working fine. However the third one i cannot even access as it is still linked to the owner. When i went to the store it was like a dont care attitude from staff. They said that they can refund me the money. I dont want a refund, i need an Ipad that is working. How can you'll sell a product and not check if its working correctly.