I've designed my IAP such that form the moment transaction is paid till the moment it is confirmed it is "tentatively accepted", and the app works as if it was

I've designed my IAP such that form the moment transaction is paid till the moment it is confirmed it is "tentatively accepted", and the app works as if it was truly accepted. Should the verification later fail, the "tentatively accepted" will turn into "failed" and the related functionality will cease to work later on. Payment systems outages like this are inevitable, and design a billing system without handling outages gracefully is just inviting trouble. On a related note, I am open to licensing the tech (both iOS code and the backend server) to anyone who is interested.