You can upgrade when you are logged into the AppSumo website:
1. Hover over your profile image
2. Select 'Products'
3. You will see a list of your purchases. You can either:
--3A. Page through until you see Bind AI, or
--3B. In the search field, type Bind and select enter and it will filter out your products
4. Click the dropdown and select 'change plan'