Here are some more details on the situation:
At the start of the game, your inventory will allow you to hold only three of each item type. If you redeemed or purchased a Chaos Pack or Explosive Pack, you should receive four of each item type included.
If some or all slots in your inventory are already taken at the time you redeem or purchase the pack, it might look like you are not receiving some or any of the items because they cannot be added to your already well stocked inventory.
However, the game has a mechanism to handle this situation. After a fast travel or checkpoint, the game will add any outstanding items to your inventory if one or more slots have become available.
This means none of your items will be lost. The game will remember how many items you should receive and add them as soon as possible.
You can increase the carry capacity for homeopathics and throwables by unlocking the Journey Pack and Throwables Bag Perks.
However, if you are certain that you did not receive the content when you should have, please take a look at this FAQ.
If you have any questions, feel free to contact us!