CollateBox offers a free 15-day trial on new accounts. Upgrades from free accounts do not qualify for the free 15-day trial. If you upgrade from a free to a paying account you'll be charged for your first month when you upgrade.
If you cancel your paid account before you are billed 30 days after your original signup then you won't be charged.
Once you cancel you won't be charged again, but you are responsible for whatever charges have already been incurred for the current billing period. For example, if your billing cycle is on the 18th of every month, and you cancel on the 24th, you'll still have to pay for the current month, but you won't be charged again after that. In order to treat everyone equally, no exceptions will be made.
You can cancel your account at any time by sending an email to firstname.lastname@example.org from the registered emailId.