Got an email saying it was a toll free webex meeting call and they needed help testing... Likely a scam - first off that's not a toll free number, it's San Fran...
When I logged in to a WebEx (teleconference) on my computer and asked it to call me for the audio portion, this is the number the call came from. If you didn't ask for a WebEx call, it's probably just someone because someone mistyped their own phone number for the call back.