If a paid plan ends and is not renewed, nothing changes for 14 days: your connected accounts stay and your scheduled posts still go out. You get an email the day it ends, a reminder at day 7 and a last notice two days before, each one listing every connected account, how many posts are scheduled and the exact date. On day 14 the accounts are disconnected and the posts still waiting are canceled. Drafts, the board, templates and your history are never deleted, and renewing at any point before that date keeps everything as it is.