I've learnt the lesson the hard way that owning your own domain and pointing MX records to an email provider whose service you pay for directly is the only sane

I've learnt the lesson the hard way that owning your own domain and pointing MX records to an email provider whose service you pay for directly is the only sane approach. That way, the service provider is obligated to provide you service, and if they ever pull any shenanigans, you just point your DNS somewhere better.