To say the Vivo Nex was a unique device would be an understatement. It was the first smartphone to include a motorized front camera module, thus saving screen real estate. Nevertheless, the OEM has announced that 2 million units of the Nex have been sold since its release in June 2018.
https://www.notebookcheck.net/Vivo-sold-2-million-units-of-the-Nex-smartphone-in-six-months.374186.0.html