Be that as it may, firstly we don't know how many of those users contribute to their revenue. We don't know the % of users who actively use the platform as there's a lot of people who make accounts, try out the features for free and then leave. And maybe a large % of the people complaining were such active users. But that's besides the point.
I understand that they're a team of 11, but it's really not hard to find a way to make it abundantly clear that such a change is rolling out. For a startup I think it's important to put some emphasis on this aspect of customer service as well - for the long run.
Happy to resolve it as a difference of opinion. I come from a place of experience where this would be unacceptable. Just something for them to think about I guess.