a woman called and left a 866... number

Got a call from this number but they didn't leave a message

Regarding KU Medical Center Physicians

This caller left a message from Boston University Oral Surgery Deprtment for an overdue balance for someone I do not know. The call back number was a 1-800 number.

I got a call from this number, and a mans voice said I called asking for some guy named Mark. I told them i never called this number and I hung up. from the voice i am guessiong the man was either in his late 20's or early 30's but i also think there is a possibility that it could have been a computerized voice as if they were useing a voice changer while talking. I am wonder if it was a prank call or something.