We also need a law that prevents them from changing the terms of service on a product someone has been using, then locking them out of it if they don't agree to the new terms.

This. So, so much.

With mandatory jail time for the managers of companies who break this law, and/or fines that are guaranteed to send the stockholders howling and demanding the executives's heads on spikes. The current fines clearly aren't enough of a deterrent and just considered the normal cost of doing business.