If your payment isn't processing it may simply be because you need to call your credit card company to verify the transaction. Please call them to let them know about the purchase.
Also, sometimes Internet Explorer gives customers so problems. Please try again with Chrome or Firefox. If that doesn't work, close your browser, clear cache and try subscribing again.
Another reason why the payment isn't processing might be that the code you're trying to use is blocking the purchase. Please try to join without it and we'll refund you the difference depending on the plan you chose.