I recieved a call on my cell and no message was left.

Says Plymouth, MI caller

I received several calls from that number recently in March 2013.  No message was left.

received 2 calls today, no message.  i don't pick up calls i don't know. if want to talk to me they are going to have to leave a message.

Called no. back after 4 calls in last 2 days on my cell and recording says they are calling me re my interest in going back to school.  Never filled anything out re such.  Did give option to remove number from call back list.

They keep calling and never leave a message. They make sure that they stay on the phone long enough to be picked up by voicemail. Then hang up. They call 3-5 times a day.