Hi,I am building an app with a unique monthly subscription model which is different in essence from the regular Apple auto-renewable subscriptions.The app is connected via API to the user's bank account and I must charge the users every month, but only after they receive their latest paycheck so it depends on the users bank account state. Plus, if the users don't have enough money in their account I would like to skip the charge.Now, I noticed that Apple IAP guidelines state that app developers are not allowed to issues subscription fee charges outside the app eco-system (must rely on the Apple IAP mechanism) but some apps (like Dave, or Brigit) have a fee model similar to what I described.Is there an exception I can make when implementing this unique subscription model and charge users directly or not?If yes - where can I find the guideline which states that its allowed?If not - how are dave or brigit doing this?Thanks!