+19056125416
This number works with skype.
You should have atleast 2 hours of credit in skype for safety as the waiting time may be very long.
Initially on connecting the call press 2 to redirect yourself to Ircc and after that press 1 every time they ask you to press a number (except when asked to enter application number and date of birth) , in the end after giving you the status of your application it will tell you to press 0 if want to talk to customer service, sometimes after pressing 0 it says all agents are busy. Then you have to try all the steps from the start by redialing. If it says please hold the line then you will be connected to a agent but the waiting time is very high sometimes 30-40 mins. Just be patient and prepare your questions wisely that you are going to ask them meanwhile, don't simply ask the status but try to imply if there is something wrong with your application so that they have to look into your application, otherwise they will just give you the same pre-cooked answers.
Hope it helps.