The cancellation process is handled through your Atlassian account.
To manage your Vansah subscription you will need to follow the steps:
Select your billing account if you have more than one
Select Subscriptions from the side navigation
Find Vansah Test Management in the Manage subscriptions table
Select Manage
At the top of the page (right hand corner) select ellipse button and click on Cancel Subscription, then review and confirm your cancellation.
Please note: Cancelling the app subscription doesn’t uninstall Vansah from your product. You can do so by selecting Manage apps within your product, and select Uninstall