WP Simple Pay Lite for Stripe doesn’t work

Hi,

I have installed WP Simple Pay Lite for Stripe and configured the Stripe Account. I tried testing the form, but when I click the button to pay does not respond (you can test it in the url).

From Stripe support say I need to contact you because you need to do the integration. For that reason I turn to you.

Literally they told me:
“they (WordPress support) will need to complete the coding that links your checkout page and your website. Please contact them, they should know all the steps”.

Could you help me?

Thank you in advance.
Oscar

The page I need help with: [log in to see the link]