If you added linked a card in-app to CheckPoints for points, you should know that it's easy to opt out.
We use a service called Plaid to link your card, meaning CheckPoints never stores your personal information (and Plaid ensures that all of your data is encrypted with the highest level of security). To see what accounts you have linked with CheckPoints as well as other apps, create an account here: https://my.plaid.com/.
Once you've setup your account there, you'll need to login to your linked accounts to verify that it's really you. From there, you'll be able to 'Manage Connections', and delete/remove cards as you please.
A second way is to simply submit a user support ticket in the app's support section stating that you would like us to delete all of your card-linked data. We'll get it cleared out and deleted ASAP!