Whoops, my comment isn't very clear, sorry. I meant: "but their account would still be active and in the hands of the thief, if there is no way to quickly deact

Whoops, my comment isn't very clear, sorry. I meant: "but their account would still be active and in the hands of the thief, if there is no way to quickly deactivate it, e.g. before receiving a new SIM card from their operator that would enable you to prove your identity to WhatsApp."