001 800 2676788
1 for English, 2 for IRCC, 1 to enter UCI 1, 1, 1, 3 to enter WP No. and Year of Birth and lastly 1 to hear the IVR status of your application. It's very difficult to get to speak to an agent. It will disconnect saying there are too many calls. You have to call multiple times and if you do get through, they put you on hold for 1 to 2 hours. The IVR is available 24/7 though but IVR information is the same as you see on portal.
I called on 18 April before strike and got connected on my 4th attempt and after 40 minutes of being on hold, I spoke to an agent, who put on me on hold for another 10 minutes to find out the information I asked about. So basically I was on hold 50 minutes to speak to him for 5 minutes.