A HootSuite account can be cancelled from the Settings section of the HootSuite dashboard.

HootSuite Pro and Enterprise account holders who have created an organization must delete the organization before the account can be cancelled. Organization members who were granted super admin permissions must delete the organization, leave the organization or have their super admin permissions revoked by the organization's creator. 

To cancel your HootSuite account

1.  From the launch menu on the left, click the gear (Settings) icon.

2.  Scroll down to bottom of window, and then click Account Removal.

3.  Type your reason for cancelling, and then click Remove Account.

Alternatively, you can click Cancel to keep your account.