I need help.

Hi,
I just registered into your platform and linked my steam account, and I got this '' Free Spin '' prize in my inventory.
But I just can't open it. No matter how much I try to open it, it is not even an interactable item. And when I go to the mystery box section it shows me the option if buying the same box that ( supposing ) I already have my inventory.
So, how to claim this box please ?
Thank you for your support.