Who called from 4153639552

Missed a call from 415-363-9552. No message left. How on Earth did they get my number?

Received call 4-4-2013 11:20am on my cell.  Called back on another line and the recording stated that it was for a national survey regarding cancer.  No company name given.

What's wrong with these Asss.... I placed num. on do not call list and they still calling...I whish I could see their face....

I just got a call from this number for the thrid time in a month. Haven't answered but it is getting really annoying has anyone been able to stop the calls??

2nd one on my cell phone in 24 hours.  I just hit REJECT and that's that, but it is very annoying.