Hey - Garret from HipChat here. That support info is not correct, and I'll investigate. All you need to do is go to the billing admin area and select the option

Hey - Garret from HipChat here. That support info is not correct, and I'll investigate. All you need to do is go to the billing admin area and select the option to cancel your paid subscription. The message there will tell you that you have 5 users and that it's OK to cancel.