It's most probably inside your Core Box. The freebie should be located in the Stalkers' insert. Here is the Monster Hunter location in the insert. It has a dedicated spot next to the doggo.
If it's missing from there please contact our Customer Support and provide a photo of the content of your Core Box (overall photo of the inserts) and of the SKU sticker from your shipping box or Core Box.
The SKU stickers looks like this:
