Firstly, log into your account on the Sling TV app or website +1- 855-740-9747 to cancel your subscription. In the upper right corner, click on your profile symbol, then choose Account Settings. Click the Cancel Subscription button.
To cancel your Sling TV subscription 1- 855-740-9747, log in to your account online, navigate to the subscription section, and follow the prompts to cancel your subscription. Confirm 1- 855-740-9747 the cancellation to complete the process.
Source: https://portal.mtaq.com.au/forums/general-discussion/75af12b2-2c85-ef11-9443-000d3acaa853