I received a response to a craigslist ad from this number. They texted and said they needed to call from a work phone and that I needed to enter the extension 98 (this ended up being the activation code for a google voice account) to speak to them. I didn't answer the first time, because this was fishy, but then I was an idiot and thought that is maybe how google voice works, so I entered the 98.

This ported my cell number to some new number and account they set up. If I would not have contacted my carrier and changed my number, they could have granted themselves access to all my google accounts and it would have cancelled my plan with my carrier, leaving me phone-less.
I called the number and the name on the other end was Thomas Luther. I do not know if this is a real line or a google voice line, but seeing as he texted from it, I believe this is a real mobile number.