No problem! To solve this problem, manually change to monthly billing and let us know. Once you've done that we'll refund you the difference.
Here's how to change to monthly billing:
Log in to Milanote
Go to 'Settings' (in the top right of the screen)
Choose 'View billing details'
Choose 'Change frequency' and switch to monthly billing
Let us know once this is done and we'll organize your refund straight away.