Apologies in advance for the cross-post, but I need to resolve this quickly before my 24 hour window for cancelling expires...

I have made a number of QR flight bookings via BA using Avios. All of the J bookings are fine and I can reserve seats via the QR call centre. However I had to make one booking in Y, due to lack of J availability, and was expecting to pay extra to plunk myself into an exit row (16k on the 77W). However the QR call centre have refused to help as I have no booking / credit card details with them, and all options on the website and app are greyed out.

I am not willing to wait until the airport and be assigned a middle in the last row, so will canx the entire set of bookings tomorrow if I cant resolve this.

Any thoughts / suggestions?

Thanks in advance.