If you are missing items from the gold upgrade please refer to this article instead: Missing items from gold upgrade
If you very recently purchased items from the Stockpile (item store) and they are missing from your in-game inventory it probably means the in-game inventory has not refreshed yet. You can manually refresh by clicking the rotating arrows icon near the bottom of the inventory screen.
Your Steam inventory page is the most up-to-date view of the items you own. If the items are shown on the web page then you definitely own them, and the game should show them soon. You can view your Unturned inventory in the Steam community here: