@angelacct 

QB Employees don't understand proper accounting and it's clear by their responses that they really shouldn't be giving advice on how to handle this.  On cash basis, you have two options for uncollectible invoices:

1) Zero out the invoice.

2) Create a Credit Memo with an item linked to an income account, not an expense account.

You don't want to use an expense account like Bad Debt Expense on cash basis because that will increase your revenue with an offsetting expense.  Although the bottom line is the same, you don't want to show revenue from uncollectible invoices on cash basis.