How to spam a phising page

I come across several phising pages a week, often very badly created, and I’m often quite bored, and would love to spam them back.

I was wondering if someone could tell me the quickest and easiest way I could run a program/script or something that would send a bunch of fake usernames/passwords/emails through their phising page, so they end up receiving a lot of useless data that doesn’t work.I understand that often these phishers use a script to verify if the data is correct, but I know a few that are definitely done manually (I know some phishers personally).

Ideally solutions that don’t require installations would be preferred, but let me know what you think is the best way I can do this.