Who called from 2154623521

I get a call from this number, (215-462-3521) I am unable to take the call, the person doesn't leave a voice mail. Later on the day, this number calls again, I answer, a man asks to talk to me, I say "This is she" ans he hangs up. I try calling back but it says " The person you are trying to reach is not able to receive your call. He knows my name...

I got a call from this number.  Guy said he was calling on behalf of Microsoft.  Said my computer was sending malware, wanted me to turn on my computer... I hung up.

They probably know your name.

This number keeps calling me but never leaves a message.

It's likely someone verifying your identity for any credit collection reason to make sure the number they have is you and is valid.  Expect more calls.