Nowhere. They can stay if they want. They just lose citizenship and the privileges of it until they pay
Discussion
The number one privilege of citizenship is access to territory.
Not sure what others you had in mind.
But disenfranchisement has a bad historical record. Think black people in the USA back when or serfs in feudal societies.
Well they lose their passport so they lose access to the world.
That was bad because it was based on race or class
If you exclude people that don't have $5k then that's class immediately.
The rest will vote to raise the tax to $50k to exclude more people.
As for access to the world that's not on most people's mind.