You can find the FAQ related to Unity subscriptions and Unity ID at the following link:
Key Questions:
Can I cancel my subscription before the end of my commitment period?
Software subscriptions are not cancellable during your commitment period and are non-refundable. This means that once you commit to a subscription for a certain period of time, you are obligated to pay all payments owing for that period. Even if you stop making payments and your license is shut down, you are still obligated to pay the outstanding payment(s) for your subscription period. Please see the Unity Terms of Service, which include additional terms for the Unity Software, for more details.
Do I own the content I create with my subscription?
Yes. You fully own the content you create with Unity, even if you cancel your subscription.
Can I combine different payment plans?
Since it's not possible to purchase multiple subscriptions on the same Organization, it's also not possible to combine different payment plans. For example, you cannot have a 12-month prepaid subscription & a pay monthly subscription on the same Organization.
Other Information:
For general inquiries, please contact Customer Experience team.