It was never established that any call came from Natalee. Call from an unknown source was jumped on as being from Natalee by many, and stories spun up around it. My first thought (way back then), was ransom demand, traced to vds.
So do you think the content of the call rumored to be "Are you calling home", may not have been the content at all? I know there was some speculation that what was being listened to may have been sounds more than voices, but Beth sure seemed to think it was important enough to detemine it had something to do with Natalee. Since there are not reports of a ransom demand what do you think the call was about?