Just got a phone call from this number pretending to be the "Tax Department of Canada Revenue Agency", saying that the CRA had launched a lawsuit against me.     As a Chartered Accountant, I immediately know that this is a fraud, because the first thing CRA would do is an audit --- either a letter requesting supporting document, or, if you operate a business, send in an auditor to see you.      After an audit (or review), they will send you a re-assessment, in which you get 90 days to appeal ---  firstly to the Minister of Revenue and next to the Tax Court of Canada.        If you do not pay, they will then refer you to their Collection Unit, and ask the bank to freeze your account (or order your employer to withhold more taxes from your paycheque).        It is very rare that CRA will launch a lawsuit (through the Attorney General of Canada) for income tax issues.

I call back to this number, questioning their office location, and they just say "Special Investigation Office, Canada Revenue Agency" in Ottawa.     They are unable to tell me the exact office location (such as Huron Road, Laurier Avenue or at Shawinigan, Quebec), or the exact tax issues or tax assessment.      And, I have not even filed my 2016 income tax return yet !!      Of course, they hung up on me right away.

I think that are randomly going through some sort of list, as my last name is Chan and I got a similar call on my answering machine. I am pretty sure that it is a Robot call, as it sounded very mechanical and did not ask for any person by name ( ie. we are a family of 4). You have provided an excellent summary of CRA`s standard protocol ..... besides, I have already received notice of assessment for 2016, on which there were no issues.

I just got a call from this number telling me they were launching a criminal investigation against me for tax evasion/tax fraud. They asked me if I had a lawyer to which I completely freaked out and started yelling at them that it was complete [***], that I work in the service industry,  and that I can't afford a lawyer. They hung up on me. I called them back, they hung up on me again. I contacted CRA to report a telephone scam.

I literally got this call this morning and im not going to lie, i have credit adjusters on my butt so deep down i felt like this was fake but i called them just to make sure. The first time i called them back it registered as an out of service number but i called them back a second time and i got an answering machine and i left message cause im heated af right now so I want to get to the bottom of this. I agree with @achan because this message kinda freaked me out and it sounded like a robot.

The prior posters have been referring to a CRA scam.  I am guessing having "credit adjusters" on your butt is not the same thing as having the CRA after you.  Robot messages are often a sign that you are being contacted by a scammer.  I think you should be skeptical of the calls and messages from this number.  If they claim to be calling about a CRA problem, that should be easy enough for you to do a fact check on by calling the CRA on a number you know is legit.