If you'd like to delete your subscription with us, you simply need to login and click on "billing" in the left hand sidebar menu, at the bottom.
Once the billing modal opens, scroll down and click on "downgrade" in the free plan column. This will downgrade you to the free plan at the end of your current billing cycle.
Please note, downgrading to free will set disable the renewal of your plan, once your current billing period end it this will disable all paid features and set all your files to expire 30 days from that point.
You can also delete your account to instantly cancel any subscription with us, to see how, see how to delete my account.