If you package tracking has "Retention" status, it is either stuck at the custom for inspection or the package was delivered but you were not there to receive it.
You should have received a slip/note from the postal office with instructions on how to retrieve the package.
If you did not receive a slip note, high chance is your package is still at customs for inspection, in which case, you may need to wait for a few days for them clear custom.
You can always track your package anytime here: https://originalstitch.com/purchase-history
