Looking into App Store or Self Fulfilled but we don't know how to get the app service to stop working once they have it on their devices. It's a subscription model that we will charge $47 per month for the service, but if they cancel, we need to cancel their usage of it. Need to know how to launch this thing ASAP. Any help?
Geez, if you are asking this because the person or people building this don't know the answer, you don't have a technical team capable of launching your "thing" ASAP.
This is such a basic technical question that you need to stop what you're doing and find a competent technical co-founder before pursuing this idea any further.
If you are in the mid of app development then I assume you had already shared this with your tech team. If they were unable to answer that then you are surely in trouble. Fire them right now! because you don't even know what they will end up building.You might end up getting a rejection from Apple store if the app is not "wired" properly.
Hope it helps.