The Battle for the Net site https://www.battleforthenet.com/ no longer seems to have the telephone form(!)
But… Boing Boing does. Go to https://boingboing.net/. You’ll see a popup window with a place to enter your phone number. Click OK, and they pop up a script on-screen.
They call you, you answer, then you supply your zip code.
Then they place calls to each of your legislators (in the House and Senate), then if you have time, they call the offices of Mitch McConnell, Chuck Schumer, and other leaders, so you can deliver the message.
I say my name, home town, and then ask that the FCC preserve the current Title II Net Neutrality rules. The staffer who answers is gonna be busy – you might chat them up though to see if they’re getting slammed. (Mitch McConnell’s office wasn’t even answering(!))