What prevents you from revoking your payment mandate at your bank?
In Europe at least, your bank must honor this request and there’s nothing your debtor can do about except spending 1000’s to recover at most 3 months of payments with the current legal apparatus in Europe.
That’s why trade unions in France maintain their own security forces, trained to spot troublemakers or hysterical militants and reign them in. Perhaps is this what makes for successful démonstrations.