It is unlikely that unplugging your device has anything to do with your subscription. Either your subscription expired for the channel you were watching and when you exited out, the expiration showed up or the show rental time that you were watching expired as there is normally a set period of time for you to watch a rental. Or the free trial period for that channel or show has also expired. Some channels have free weekends, etc... and it that expires then you can no longer watch. It is also possible that the show was available for a set period of time and was removed or no longer available for that streaming channel/service.
I would suggest checking your subscription for that channel by either checking your Roku account (if you signed up that way) or checking the subscription where you signed up for that channel.
