TL;DR: We've been on the Cloudflare Business plan ($250/month) for years. They suddenly contacted us and asked us to either pay them $120k up front for one year of Enterprise within 24 hours or they would take down all of our domains. While this escalated up our business we had 3 sales calls with them, trying to figure out what was happening and how to reach a reasonable contract in a week. When we told them we were also in talks with Fastly, they suddenly "purged" all our domains, causing huge downtime in our core business, sleepless nights migrating away from CF, irreparable loss in customer trust and weeks of ongoing downtime in our internal systems.
Regardless of whether this is the whole story or not, the advice at the bottom to at least limit your CF dependence is a good idea.