Dealing with a stolen phone is incredibly frustrating, especially when someone is ghosting your texts. To answer your question, you can use this
site to send localized tracking links via SMS, but it doesn't support sending anonymous voice messages directly. However, you can use a temporary VoIP burner app or a Google Voice number to make that call or send messages without giving away your actual alternative number. This keeps your personal information safe while you try to negotiate getting your device back. Just be careful and prioritize your safety if you arrange a meetup!