Who called from 8157520063

returning the call resulted in endless ringing or busy signal...no answer

I got a series of calls over several days from this number and numbers within a few numbers( 0081 - 0068 ) on my cell phone. I didn't answer but because of the annoyance I called them all. One said it was out of service. The others put me into a mailbox for an NIU annual fund raiser. They said they were trying to contact all alumni and parents of students. I didn't leave a message.

Any ideas on how to get off their list?  The constantly call my cell phone.

"Free roof inspection" to number on do not call list.