I think a decent analogy would be a grocery store. Sure, you've gone there and got free samples for over ten years, but now they feel those burger bites and cheese dip w/ crackers weren't actually helping them sell more product.

Do you expect the grocery store to give ample notice? Should they change their mind when people complain?

Admittedly the analogy isn't perfect because the samples aren't a major portion of the grocery store's cost/business, but it's still decent.