While i can understand a price increase, this is really short notice, especially the time frame to make your next payment ahead of time. I think at least a couple months would have been a lot better for most people.
I think reducing groups for Basic members will hurt the Stores and and Creators rather than encourage people to upgrade to Premium. If they could not afford Premium before the price increase, they surely won't be able to afford it now. This will likely encourage people to make more Basic alts in order to get access to more groups.
Please reconsider these changes!