Re "What are you talking about? I can login to Qobuz on my browser, click my name in the upper right, drop down to settings. The literal second link under My Account settings is "Change my payment methods"
It wasn't like that 8 or 10 months ago when I had this problem. I can assure you as I've used streaming accounts for a long time, and on Tidal it was easy to do as you describe. And it doesn't change the fact that it took them a month for a non-reply. So maybe they finally fixed it. My friend was having another account pairing/setup problem with his Bluesound Node, and they only responded in French! He's bailed and switched to Tidal. That was last week!