I had done my homework and had the exact flight I needed to add. When it was clear the person had no idea what they were doing (kept giving me wrong info and didn’t know what a oneworld Classic Flight Reward was), I politely ended the call and explicitly requested for NO changes to be made. Despite this they must have clicked on something, not sure how or why, but my whole booking was affected and they refunded 1 x 318k points. I avoided making any future calls after the 25+ calls after that, that’s how long it took to find someone competent to fix the whole mess! It was an agent in Manila and she was an angel, saved the whole trip for my partner and I.