Instant recalls cannot be used from Smugglers' Den because it would make no sense. How would the game guess what you want to (instantly) recall?

Instead, you need to go to your Stronghold, "Underway" tab, choose a group of your troops going away from your haven, and click "Cancel" ("Belay" in "piratey" English):

If your units were sent from your haven more than 50sec ago, the game will ask if you're sure you want to use one of your instant recall items.

Note: This works only on individual parties (unit groups). In other words, "Recall all" will only work for rubies.

If the game is not behaving for you as I have described, please state so and the agents will have a look.

Hello, captain! You can use them to cancel movement of the battle squads moving only forward to the target: Pirate Stronghold => Underway => click on the red cross => press "Yes" in the pop-up message.