It's possible that the payments are directly deposited to the bank register when receiving them, wrightboys43.

This is also the reason why you can no longer change the account since they're already posted in your register. Let's make Undeposited Funds the default account when receiving payments in QuickBooks Desktop. Here's how:

1. Go to the Edit menu and select Preferences.
2. Click Payments in the left-hand menu and proceed to the Company Preferences tab. 
3. Check the Use Undeposited as a default deposit to account box. 
4. Click OK. 

Here's another guide for more details: Deposit payments into the Undeposited Funds account in QuickBooks Desktop.

Let me know if you have follow-up questions.