Which airline should I contact when adding infant to reservation?

Hello!
I need some help. I have been trying to add an infant ticket to my Air Canada business class ticket that I booked through Krisflyer for the last 2 months and am still having no luck.
My husband and I are travelling from Melbourne to Vancouver in September with Air Canada using points from Krisflyer. We booked our tickets easily with Krisflyer and at the time they said we will need to add the infant later and it could not be done at the time of our booking.
Since then I have tried to add the infant through Krisflyer to get a ticket on points or pay for a ticket but they say this is not possible. I have called them multiple times and they keep referring to me to Air Canada. Air Canada says they can not issue the ticket for the infant as the stock is Singapore Airlines stock and it must be booked through either Krisflyer or Singapore airlines. They say that the ticket does not become “Air Canada” until a few days before travel and that is the only time they can add the ticket. I have called Singapore airlines and they say they can not issue an Air Canada ticket. I have tried to speak to the “senior” member of every team and am still stuck. Does anyone have any advice on who should be booking the infant ticket?
TIA

Hi ginag,

I have asked a few friends that have had experience with this. They said it is generally the airline program that you redeemed with (Krisflyer) that has to issue infant ticket. With Krisflyer, you generally have to pay 10% of the revenue fare for the infant (in lap). I would suggest keep trying and escalate to a manager/supervisor. I know it is frustrating but not every agent is equally skilled/experienced. I have read of point/travel bloggers that had to get the 2 airlines into a conference call to be able to get someone to actually do something as they were initially finger pointing.
Good luck and report back if you had any luck.

Thank you! I will call Krisflyer back and try again. Love the idea of a conference call. Will post back with update.
Thank you again