Missing key to unlock premium chest

For the past few weeks every time I've logged in I get the hextech key box come up, and although I've used the system before and opened hextech boxes from keys in the game, it keeps popping up. I believe this is the case because I have yet to open my premium free chest you give to everyone for free. The problem is I do not have a key to open it. The open button when the box is highlighted is grayed out and I am unable to use it. After watching a youtube video of someone else opening the box and googling the problem, it seems that I was just not given a key. Can you add 1 premium key to my account please.