Go to https://www.historyvault.com/account. If you are not signed in to the website yet, you will be redirected to the homepage of HISTORY Vault. Click 'sign in' in the upper right corner of the screen and enter your login details. Click your name in the upper right corner and select 'My Account.'
Once you are signed in and are viewing your 'My Account' page, you will see the platform you originally subscribed through (i.e. HISTORY Vault website, Google Play, Apple's App Store, Apple TV or Roku) with instructions on how to cancel on that platform or to update your payment information. If your account is currently inactive, you will see an option to reactivate your subscription.