If you wish to quit during the trial period, there is no need for you to do anything. After 14 days your subscription will be automatically canceled if you didn’t add a credit card. If you have a paying subscription and ask to stop it, it will be automatically canceled as well, at the end of the last billing period you paid.
If despite everything you want to definitely delete your account, here is how to do it:
1. Log in to your account
2. Click on your Firstname on the top right corner of the page, then on “User settings” in the menu
3. Click on the “delete account” link at the bottom of the page
4. Confirm that you want to delete your account
Done, your account doesn’t exist anymore.