The first panel, where you enter your payment information, is just for establishing payment. There's another screen where you apply the code and confirm your purchase. Hope that helps, there's still a few more hours before the code expires!
On Windows you can use "telnet" from the Command Prompt to do the same thing. Take the replit.dev component of the ssh command (the part after the @) and run "telnet [replit.dev host] 22". You should see "Replit-SSH-Proxy" in the result. [3/3]