Reposting what I said to another but:
I reccomend signing the ACLU petition if you are an american. The ACLU has more political power than change.org https://action.aclu.org/petition/mastercard-sex-work-work-end-your-unjust-policy
Also consider: Contacting Members of Congress/any other government officials of the dangers of the mastercard/visa controlling the worlds payment and preventing purchase of legal goods they don't like Contacting Mastercard/Visa to complain. Collective shout did the same thing with only ~1000 people, there are more of us than there are of collective shout. Complain that fringe groups like Collective shout have targeted legal content. Please be respectful however. If you have invested in funds that own stock in visa/mastercard, or even own stock in them directly, contact about concerns of Visa/Mastercard cutting off revenue streams due to anti and fringe group pressure.