Received call at 05:33 am.  No message

Call received at 6:00 A.M. yesterday, at 1:45 A.M. and 2:15 A.M. today. My phone doesn not use the type of ring announcing a long distance call and it should. Each time It rings twice and stops. We did not have time to answer. I tried to call back this number. It rings several times, than stops rigging and I don't hear anything for a while and than I get a voicemail message saying "the person you are trying to reach is not available. Please leave a message"...

Calls once a week at about 4:45 am. Left no message.

called 3 times yesterday at 4:50am

hi peeps, got a call today at 6:54 didnt get a chance to answer, called back rings a couple of times then no more ring tone.
guess its a spam type or something