If you use on both Android and iOS, you will need to follow these steps on the device you upgraded with.
Step 1: Tap 'Projects'
Step 2: Then tap 'Settings'
Step 3: Tap 'Manage Subscription'
Step 4: Scroll down to 'Options' and tap 'Switch to Monthly'
Hint: if it says 'Switch to Annual, you're already on a monthly subscription!