Black screen when opening chest [CLIENT]

When receiving my 3rd key fragment i fused them together to make a key which i used to open a chest, but when i clicked open the screen where you would see the chest was black. So i went back to home page, thinking it would fix the problem, to find when i went back to loot the chest i opened and key were gone leaving no sign of a new skin, champ, ward, or icon. If this is read i would like my key and chest to be refunded back. If you choose not to or cannot i fully understand