Elias here with Shopify Support. Thank you for this inquiry.
I hope you and your business had an amazing Black Friday and Cyber Monday! I understand that eCheck payments can be a bit of a problem, especially since they take a longer time to clear. Blocking eChecks payments is not a setting found on Shopify; however, you can block eChecks payments directly from your PayPal dashboard.
Is this what you were looking for? If you have any other questions about payments, don’t hesitate to let me know in the thread!