How to find out what kind of merchant is connected to the site?

Question

Electronic commerce

An example of a site where you need to find out what kind of merchant is there - https://rapidgator.net
Now I am collecting a list of all possible companies that provide services for connecting various forms of payment to the site.
1. Large ones seem to be known, but there are still a lot of smaller companies. Where can I get/collect this information?
2. Is there any way to find out which merchant is on a particular site (if there are no links or redirects directly to the merchant's pages)?
3. I will also be grateful for links to specialized resources / forums where I can get acquainted with the issue.

Answer 1

1. by interviewing each smaller company
2. indirectly by extract. VISA, in general, does not encourage anonymity, so there will be something in the statement, but it may well be the legal entity for which it is open, and not the bank
3. www.banki.ru from whites, forums of real cases - from the rest