After clicking the BUY NOW  button, you are given three options for payment. These are the only payment options available:

Credit or Debit Cards
Paypal - Not available in some countries
Wire Transfers - Not available in some countries
Bitcoin or other Crypto currencies

If one of the methods above are not available even though it was supposed to be available, there should be something wrong with your local network.

In this case,

You may need to turn the VPN off (if enabled) and clear the browser history.
The missing payment method you have been looking for (e.g., PayPal, Bitcoin) might not be available in your country/region.