@Gilgamesh0x if the game is really no longer registered as yours in your lib, theres little to nothing you can do other than to wait for a human reply for your ticket, as while the lockdown is still in place you wonāt be able to add it by yourself back there, even if you still have hours registered on your account.
you could also contact valve support and explain the situation and see if they can do something about it, preferably with a non-google translate english if you can or just write it in portuguese.
Contacting Steam Billing and Support