If you still wish to proceed, here are the steps to easily cancel your plan:
To cancel your plan:
Click on your username.
Select "Subscription" from the dropdown menu.
Click on the three dots on your plan
Choose "Unsubscribe"
Select your reason and write down more details. (Make sure it's not too short so the confirm button will activate)
After doing this, your subscription will be set to be cancelled by the end of your billing cycle to enjoy your remaining credits and create more videos.