This question has been asked 10 years ago but I didn't find a solid answer for this so I will try again.
I am building a website that requires a Paypal payment in order to input information. I want when a person pays the amount of money (by clicking a Paypal button) to be redirected to an Information page. (the person should enter some information on this page)
So far so good, I have done this. On my initial page, I have created a working Smart Paypal button (like this one - smart paypal button example) which redirects me to the Information page. However, my first problem is: When a person pays with Paypal and gets redirected to the Information page and then he enters some info and moves to the next page with the results. Now he can click "back" on the browser and enter the information once again. I don't want this to happen. I want a person who has paid to be able to input information only once.
My idea is simple, I want a 3-paged website, first page - Payment page, second Page - Information Page and third page - Result page. I want only the people who paid to be able to access the information page.
Could you guys please suggest to me any ideas how can I overcome these problems?
