The document summarizes CrossRef's billing policies and procedures in 3 sentences: Billing is done annually for membership fees on January 1st, with quarterly deposit invoices billed on March 30th, June 30th, September 30th, and December 31st. Friendly payment reminders are sent automatically 15 days before and after the due date, and if unpaid after 105 days, system access will be interrupted. The document provides examples of reminder emails sent to members with past due invoices, noting that services will be interrupted if accounts are not brought current by specified dates.