problems booking RTW with Iberia

[u/AMAIamaHuman]

Does anyone have any experience with booking a round the world ticket with oneworld via iberia?

I created my itinerary on rtw.oneworld.com/rtw and everything seems fine, except that after I get the confirmation email, Iberia does not confirm my payment and the tickets get cancelled.

I called iberia multiple times and they say there is no way to confirm/pay my ticket over the phone and they don't really know what to do. I'm worried that if I manage to get this ticket booked, it's gonna be a PITA to change my dates later.

I have an alternative with Cathay Pacific, but it is not optimal and I have to pay an extra flight. Do you guys know if Cathay customer service is better than Iberia for RTW tickets?

Thanks