Brazilian best stamps not issued and not circulated in 2012

In 2012 I read on the website of the Brazilian post offices that would be issued beautiful stamps on the passage of the Olympic and Paralympic flags of the British for the Brazilians. These are a pair of "Se-tenant" each composed of 3 stamps: one on the Olympic flag and another on the Paralympic. During months when I visited post offices, including the philatelic  post office, I not found such stamps. The Post online shop , which makes online sales also never provided these stamps... Actually nobody knows about these stamps and all philatelists I know also do not know and never saw them. Neither dealer has them. These seals are not on the official list of stamps issued in 2012, but interestingly, the post office is disclosing voting for best stamp issued in 2012 and such stamps are competing! ... so if you receive a letter with these stamps mint or find them: keep them, even if they do not have much value it is an interesting curiosity for your collection.