You may not use, on a Jewish festival, any item that was outside the techum Shabbat when the Jewish festival began--even if a non-Jew brought it to you.
SITUATIONYou arrive on a flight but your luggage is delayed and delivered on Shabbat or a Jewish festival. Or, a package is delivered to you then.
WHAT TO DO  If the airport or delivery warehouse is within techum Shabbat, you may use whatever is brought to you. If the airport or warehouse is outside techum Shabbat, you may not use the items until enough time has passed after Shabbat (or the Jewish festival) for them to have been delivered from the airport or warehouse.