I got a code for dreadknight garen, but i cant redeem it??

So i got the promo code for dreadknight garen, but when i try to redeem it under "Redeem codes" it just gives me the message "There was a problem fulfilling your store items.

Ive already seen some year old boards on this, and usually an admin comes and adds the skin to your account for you. I hope you can do this to my account as well.

PS: I would have submitted a ticket for this, but for some reason i cant.