If you have received “return to sender” you can resend the card. The recipient can still register it up to 1 year after requesting their address. It’s quite a long time. Maybe you will be able to send to this country again during this period.
Here, in another topic someone very smart answered your question about drawing addresses in cases such as this one 
:
I would also like to mention that I have an “expired” card to Russia, which I cannot send, because I drew the address shortly before the correspondence between our countries was suspended. I’m sure we’re not the only ones in this situation.