Who called from 4152519813

call me twice in two days 202-506-9784 was the number they use

Received call from Julie Smith, electronic message from IRS, need to contact immediately or legal action will begin.  Two calls today. Same as Danny above.
Scammers.  Called back and first dead air.  Second voice mail with NO reference to IRS.
Contacting IRS  and FTC and FBI

These calls are not coming from the IRS or anywhere else in the US government.

Here is a story from FOX 13, Tampa Bay, Florida about these calls.  It's the best explanation I've found so far of these calls as well as what to do when you receive one and to whom to report the call and how:

http://www.myfoxtampabay.com/story/26206940/2014/08/05/phone-scam

Got a call from this number same message said they were the I.R.S. I paid my taxes.  I know that this had to be a scam,  no answer when I called back.

They impostor as IRS agent to get to your bank account or set up credit card payments etc... Not a very smart people in any way, however older people, who those not aware of how the government organizations system works in country might be a victim of this type of fraud.