Hello Matthew Leeden,

We can turn off the online payments option through the Custom Form Styles. Here's how to do it:

1. Click the Gear icon in the upper-right corner and select Custom Form Styles.
2. Look for the template and click Edit.
3. Go to the Payments tab and make sure to remove the check mark for Online payments and Direct Debit.
4. Click Done.

You can also set Preferred payment method for that customer.

1. Click Sales on the left menu and go to the Customers tab.
2. Look for the customer profile and click Edit.
3. In the Customer information window, go to the Payment and billing tab.
4. You can leave the Preferred payment method field as blank.
5. Click Save.

If you have additional queries about this, please let us know.