Is this on steam or itch.io? Anything about steam taxes is to be held responsable by you, you got to correctly do it. If you want to only sell in brazil you need to use steam region lock features that will make customers unable to buy your game anywhere but brazil (yes the other regions like mexico, peru, chile, etc will not be able to buy your game).
If this is itch.io you need to fill out paperwork to not get tax withholdings. I am assuming you didn't do this and might need to contact support to redo it.