Update / Change Payment Details isn't working

[Rhauri]

I'm UK based.
I want to change the card for my monthly Spotify charge.
Account Overview > Your Plan > payment details > Update
Takes me to https://www.spotify.com/account/subscription/update-payment-details/

I click the top "Credit or debit card" option (the other option is PayPal) and then I get 3 flashing dots below that imply it's loading the payment details input bit, but after 10 minutes, nothing.
I've tried on 4 different browsers, all give the same lack of progress.

[bstaton]

Over ONE YEAR LATER, and I just got a fix. I switched from WiFi to mobile data and it worked.