If you cancel your Premium Team subscription while a coupon code is still active, at the end of the trial period outlined in the coupon, your Team will automatically be downgraded to Free.
If you cancel within the trial period, your Team will automatically be downgraded after your free trial runs out, and you will not be charged. However, if you do not cancel, and you enjoy Premium, payment will be processed immediately following the end of your trial. If payment cannot be processed due to an issue with a card, you will have 7 days from the end of the free trial to update your card information to continue using Premium. This information will be provided to you through a supplementary email. If by the end of these 7 days, you have not updated your card, your Team will be automatically downgraded to Free.
For more information on what happens to your Premium Team when it is reset to Free, click here.