"This message is intended for ____ ____. I'm with SDA investigations. You're being under investigation under case number 551405. It's very important you give me a call back as soon as possible. My contact number is (904) 726-1678."

Sounds like some payday loan collector trying to scare someone. More info here:

http://800notes.com/Phone.aspx/1-904-726-1678/3

SDA Processing is:
Smith, Dean, & Associates
101 Century Drive, Suite 107
Jacksonville Fla 32216
904-726-1678 ofc
904-721-3713 fax