Hi, I get the same problem too – on a 3rd generation iPad (Safari iOS 9.3.5) it goes straight to the ‘thank you’ page after the button is pressed without going to the card input form.
It otherwise works properly on the latest versions of Firefox (Win 10 desktop), Edge (Win 10 desktop), IE (Win 10 desktop), Chrome (Win 10 desktop), Chrome (Android tablet), Safari (iPad Air 2). As well as on Safari (iPhone iOS 10.3.3).
