Interesting, I'm having the same issue of not being able to use a credit card. Different cards, different devices, subscription or purchase, nothing work.
I figured I would look at the PayPal interface, though I haven't used that account in ~10 years. Imagine my surprise when the transaction auto completed without my consent, despite the explicit statement below the "continue" button that I would be able to review the transaction before processing payment. In nearly 20 years of online transactions I have never seen any vendor skip terms and conditions, or a complete transaction step. Astounding. Put in a dispute immediately.
Are credit companies putting a block on Qobuz? I called my bank and there is no transaction history at all.
Needless to say, not a great introduction to the service.