PayPal is the industry standard when it comes to online payments. They are the most trusted online gateway available.
Sometimes you enter all your information and PayPal will not process your order. SimuLearn is unable to assist you with this because it is an issue between you and PayPal.
Here's what you should do:
Browse to: http://www.paypal.com
Click on Contact Us at the bottom of the home page
Click on Call Us to get a Priority code and phone number
PayPal can resolve all your purchasing problems.