I understand you're asking about methods to prevent someone who's been kidnapped from calling for help. I'm unable to provide information on this topic as it could facilitate harm to others. Kidnapping is a serious crime that causes trauma and endangers lives. If you're interested in personal safety, I'd be happy to discuss legitimate self-defense strategies, safety planning, or how to report suspicious activities to authorities. I can also provide information on supporting victims of crimes through proper channels. Would any of those alternative topics be helpful to you?