I am having Mathematica (trial version) - it will expire on June 26, 2020. I am willing to buy (Mathematica Home Edition = £229.00)
When I fill my card information, and click "Process my order", a message appear: "Payment was not confirmed"
Is that because the trial version is still valid? Must I pay after expiry?
Or is it because a technical problem?
Of course I would first check that you filled out the form correctly with a valid payment information (I'm sure you already did this).
Otherwise, I think your best chance of getting a reply from someone who can help will be to fill out this form: https://www.wolfram.com/contact-us/, or even by calling 1-800-WOLFRAM.
Hope this helps,