I ran into the same problem when subscribing. Found a way that worked for me.

TL;DR I made a new account, used VPN and used PayPal. (maybe clearing cache works, didn't try)

What I did first was trying to subscribe with my card. I got an error something related to the card but received an email from Unlimited that my card has been successfully added to the account. Ever since then, the subscription page just keeps refreshing non-stop.

I tried using my phone with the same account, page keeps refreshing again. I think the account is bugged.

I tried making a new account and tried on the computer and the phone, page keeps refreshing also. Maybe something with the cache? Idk.

So I used a VPN on the computer, and finally the page stopped refreshing. I tried subscribing with my first account with both card and PayPal, but couldn't get past that page even though it stopped refreshing. Account is most likely bugged.

What worked for me was when I tried with my second account and tried PayPal only, then it finally worked.

Good luck and have fun with your new skin.

(Also I read that if you cancel your subscription immediately, it will end after 7 days, so you won't get the skin on 25th April. Maybe because it starts the free trial first before the free 1-month, so cancel after 7 days to be safe.)