I have a car for sale on craigslist. this # texted me with questions.  as soon as i texted back, i was bombarded with automated texts asking me to text a given PIN back to that number.  that sounded a lot like a scam to charge me money so I called the number instead, which resulted in an immediately disconnected call.  I don't think they can charge my phone account if I didn't text the code back to them, so I think I'm clear.  will follow-up if not.