I Got a call from this number as well. Did not leave a VM.  I'm in Austin Tx

Got a call from this number. When picked up no one says anything and when called back get error saying,  "791 the number you dialed is not in service."

This is what White Pages says:

Area Code:210    Carrier:T-Mobile    Full Number:2103600199
City/State:San Antonio, TX    Zip:78288

Received call - answered - slight pause then someone greeted me as representing something like 'Guardian Services' - I hung up on him

Two calls from this number today, 12:24pm cdt and 2:14pm cdt.  
Marketing for Guardian Protection Services--alarm systems.
Politely told the first caller we're not interested.
Second caller didn't believe me that someone already called...I asked him to take me off their call list, he claimed theres no such list, so i asked him to put me on their DNC list...he said he didn't know what I was talking about.  Complaint time!

Got a call from this number today, 7-23-13, from someone named Ben, trying to sell a home protection plan from Guardian Security, whom he told me is affiliated with General Electric. Since my husband and I just recently bought a house, and we don't have any kind of alarm system as of yet, I was interested. However, was sparked my suspicion was when I was setting up an appointment with one of their representatives, he asked for the last four of my social number, my date of birth, and the last four digits of the card I would be paying the future account with.
I went ahead and set up an appointment, after expressing my concern with giving Ben my personal information, and then asked if I could have a phone number I could reach his company at in case my husband had any questions later. He insisted that he did not have one to give me.
Definitely on the watch for something criminal now.