الجواب حامدا و مصلیا
With regards to the inquired about situation, it is necessary for those who recited the Talbiya for performing Umra after donning the Ihram, and was then stopped at the airport and sent home because of the Corona Virus due to which it wasn’t possible for them to complete their Umra to come out of the state of Ihram. They, or someone on their behalf, must slaughter an animal as Dam within the boundaries of the Haram. After this animal will be slaughtered, they will be free from the restrictions of being in the state of Ihram and they will once again become “Halal” (i.e. one who is not in the state of Ihram). However, after they exit the state of Ihram, they will also have to do Qaza of their Umra.
And Allah knows best.