Do you store my credit card details?

No, we do not have access to your credit card details at all.

They are stored securely by the relevant payment gateways to allow for refunds to be processed if required, however, we cannot see the numbers.  

If you have signed up for Shopify pay, your credit card details may have been stored from a purchase you made at another online store on the Shopify platform.
For more information on Shopify Pay please visit https://shop.app/what-shop-does