I had chatted with someone who is no longer listed as a member of Agnostic.com - also had talked on phone many times and messaged on Facebook - suddenly is no longer on my FB friends list and did not respond to the voice mail I left. I have a feeling that mental and physical health issues had some kind of impact. I feel a bit concerned a bit sad, but that kind of stuff happens.
If you think you are justifiably worried maybe contact someone else this person is close to?
 kmdskit3
                                                
                                                Level 8
                                                June 15, 2018
                                            
                                                
                                                    kmdskit3
                                                
                                                Level 8
                                                June 15, 2018                                            
                                        We had not met in person and live hundreds of miles from each other - we had talked on the phone maybe a couple dozen times and I really enjoyed the phone chats. I left a message on voice mail, so I did what I could .... it is what it is.