Where are you located?
Not sure whether the mentioned „recent changes“ have been since April. If not I can recommend to call the Frankfurt Office (in Germany) of SQ. They helped me quite good on the same matter back in April.

They needed all details, forward then to another department and approx 3-4 days later I received a call from SQ agent who was asking for cc details and he finalized the booking then.
I have to note that there have been some issues later on since they put the redemption & the paid (infant) booking into one confirmation number but their system showed the redemption as not ticketed and started to send reminders to finalize the booking.
I had to call 2-3 times until it was solved and all tickets correctly sent by email to me.