Earlier quoted context omitted.
What would you want business to do ? See that customer is not active then go ahead and remove their subscription?? Lmao then you will have customers asking why did you stop my account. Clearly you have not faced customers before.
Why not send a message reminding them of the service, and giving an easy one-click way of cancelling? You could include some info on how they can use your service as well of course.
Would you put up a sign reminding them to stop stop dropping $5 bills?