Payment appears when it can actually be made
The payment screen offers the button once it can take your card details, and points to Support when payment cannot be made there.
This update settles the screen where you pay for your licence. Buying JUDLEX is a two-minute errand: you look at what it costs, type your card details and go back to your work. The screen tells you, at every moment, what you can do.
The button appears once the screen can take the card
The button to pay is available once the screen has somewhere for you to type the card number. You pay inside the application, in the form itself, without going anywhere else or starting again somewhere new.
That form belongs to Stripe, and your card details do not pass through JUDLEX servers.
When you cannot pay there, the screen points to Support
There are things about a payment that you cannot put right from your own computer, and that Support can. If payment is unavailable at that moment, the screen tells you so and gives you the route instead of leaving you looking at a notice.
The tariff screen, where you see what the licence costs, carries that same Support button for questions about it.