Can't top up from my dr card


I am trying to top up from my dr card, which has already been verified. But after I enter the cvc, the screen goes nowhere and the ‘top up’ button isn’t working. What am I meant to do?
I have spent nearly an hour on the Support ‘chat’ trying to work out why I can’t top up my card, and I still don’t have an answer.
Is Revolut always this useless? The support person is taking about 5 mins to get back to me every time I type anything.