Thanks for sharing that information but I don't think it's the IO calling you. If it's government or any legit business, their phone number or company name should at least show up on your CID, not withheld or come out as UNKNOWN.
I used to get calls from unknown phone numbers before and most of the time, they're only telemarketers, solicitors or collectors. For one, I don't owe anybody any money. I also don't buy from telemarketers and I am on DNC. In addition to that, I just don't trust charity foundations. You donate $100 and only $1 goes to the needy. The rest, $99, goes into the solicitor's pockets. So what I do, it's either I ignore them or if I am bored, I pull up pranks. I get my prank tips from the consumer complaint site called CALLERCENTER and boy, they sure are effective!
hello! just so you have an idea what I am talking about.... I got this info from one of the members of this forum

Quote from: peru87 on 12 January 2012, 20:53:24
Hi!
I have been following this forum for the past few weeks, but never had anything relevant to post. I'd like to thank everyone for been so helpful with each other, and creating an amazing group.
Today I got a call from a blocked number, did not answer until the third call –three-to-four-hour intervals between calls-. It was CIC, informing me that I have been approved for second stage, and will be landing this Monday. So, if you happen to receive a call from a blocked number DO NOT IGNORE THE CALL, as it may be CIC delivering good news.
Wishing you all the best,
A
Application received: January 20. 2011
Started processing: February 28. 2011
AIP: January 4, 2012
DM: January 12 , 2012
Landing: January 16, 2012
So there, just hoping that I'll hear good news just like this one!