>> Then, suddenly, they called us 2 days ago and said they are going to de-activate the Hack Club Slack, including all message history from 11 years, unless we pay them $50,000 USD this week and $200,000 USD/year moving forward (plus additional annual fees for new accounts, including inactive ones)

> This was a mistake.

Calling a customer and extorting them for $50k USD this week and $200k USD per year going forward is not "a mistake."

It is a business decision which your organization made and did not expect to be held accountable for same.

> We appreciate you, Hack Club ...

You have a very different definition of "appreciate", unless you are using it in the accounting sense[0].

0 - https://accountinginsights.org/what-is-appreciation-in-accou...