I did call support...waited 45 minutes, but I got a pretty good solution. Here's the deal. You can't deselect those options on the custom forms screen. Period. If you deselect one or both, they just reappear. You can, however, deselect one or both on the "new invoice" screen, and the choice will stick for future invoices.
I initally found that on a new invoice screen, there was a blurb that said to select ACH or Credit/Debit card payments, but there were no checkboxes! Intuit Customer Support said that this is because I selected HTML invoice delivery. Here's the process they gave me to change it to "Online Invoice" delivery so those boxes will appear in the New Invoice screen.
1. Click the gear icon.
2. Go to Account and Settings. Close the Company Profile overlay if it pops up.
3. Click Sales in the left-hand column.
4. Scroll down and click the pencil icon to the right of Online Delivery.
5. Under "Additional email options for invoices, change the drop-down to "Online Invoice".
6. Save.
Once I did that, the options appeared on my new invoice screen, and I was able to deselect Credit Card Payments and leave only ACH Payments selection. And the selection stays in place for future invoices until it's changed again.
