How is this possible?

1. my cell phone sits on a table at my residence----the phone will ring if anybody calls.

2. I hear a soft 'beep' but the phone has not rung. The phone lights up momentarily as the 'beep' sound is heard

3. There is no one on the line but I see that someone has left a voice mail in my voice mail box--the voice mail has just arrived---it wasn't there a few seconds ago. I call the voice mail box and give the code---and listen to the voice mail -------it is a harassing voice mail

4. Now I check my incoming call record---there is no record of a call and there is no record of the phone number of the person that has sent the voicemail.

5 So what has happened is that an unknown person has somehow deposited a message in my voice mail box without having left any record at all

6. I have inquired of my Iphone 4S people and they don't know how the above could be possible but they refer me to my cell phone provider with the question

7 The cell phone provider (Straight Talk) don't know how that is being done (I am receiving these annoying voice mails daily and at irregular times.

8. I have made a formal inquiry of straight talk for a transcript of all incoming and outgoing calls within a time period which covers at least one of the voice mails.----I am wondering if it will show any record of how the message gets into my voice mail inbox----and whether it will identify the source of the call----the telephone number of whomever is placing the voice mail message in my box. I have not received the transcript and am told that it may take as long as 30 days for this to arrive by mail at my residence----they will not send it any other way.

I am wondering if anyone out there on this forum might be able to tell me how this is happening and what I can do about it? (I could 'block' the caller if I knew their phone number---but as yet I have no number to block.)