I created an HN account solely to share this. A couple of years ago, our edutech company experienced a fourfold increase in Slack usage, was given weeks in notice too. We promptly transitioned to Google Chat (which we were paying for through Google Suite). Back then, Google Chat was quite inadequate, but I must admit that it now fulfills nearly 99% of the functions we used Slack for. Considering the numerous integrations with Google Suite products, it might even exceed 100% now. However, Google Suite promptly raised its prices when they integrated Gemini. Nevertheless, the Google account manager provided us with significantly more advanced notice and a substantial discount.
Providers will increase price but multi-fold adjustment + for non-profit should really inform way in advance.
Moving from one proprietary app to the next isn't a solution. No matter which commercial service you choose, there will be an attempt to squeeze more profits out of you sooner or later and you will have to pay up or lose your data.
The lesson here is that proprietary software is for suckers. Bite the bullet and move to an open protocol with FOSS clients.
Providers will increase price but multi-fold adjustment + for non-profit should really inform way in advance.