Wrote out a brief script to help out anyone in need of it (including myself). More knowledgeable anons, feel free to correct anything I might have gotten wrong here. Please call your reps:

“Hi there. I am calling to encourage your support for house bill H.R.987 (or senate bill S.410), the Fair Access to Banking Act. I am a resident of [state] and find the idea of politically motivated debarking incredibly concerning and want to see it regulated before it gets out of hand. It’s already had an impact on personal defense (firearms), entertainment, and other forms of free expression. Those speaking out against this behavior from entities such as MasterCard and Visa have been getting deplatformed in recent days. It is unconscionable behavior that deserves scrutiny. Thank you”

(You may be asked to leave your name, zip code, and phone number. Add to the script as necessary. Takes less than a minute).