I have to agree with the other posts here.
For whatever reason she wants to move on, it happens, probably nothing personal. I'd give her a ring or text although she may have now got a new number anyway.
In answer to the original question though, you can pay to join AW's "Telephone Directory", 5 credits for 24 hours, which allows you to filter for only SP's that are showing a phone number. I don't know whether there is a reverse search facility as I've never used the service.