Remove successful payment page from indexing?

Question

Search Engine Optimization

Hi, with each client payment on the site, Yandex adds a successful payment page to the index, each time this search robot is a unique page due to the addition of payment data to the url. After a few days, these pages are removed from the index. Here's the webmaster:

I heard from the side of my ear that it's bad for SEO. Is not it?
How to fix this problem? The file is on the server, there is no standard hosting structure with htaccess.

UPD
This is WordPress, there is a yoast plugin, there are such parameters on the page, maybe they will help?:

Answer 1

robots.txt
Disallow: /uspeshnaya-oplata-gymnastiki/