I'd be happy to help you account this cash so you can apply it to your customer's invoice. Let's get started.
You can create an account to record the stolen cash.
Select the Gear icon in the upper right corner.
Under Your Company, choose Chart of Accounts.
In the Account Type drop-down, select the account type.
In the Detail Type drop-down, select the type of account you want to create.
If more than one choice appears in the Detail Type field, select the type of account you want to create.
In the Name field, enter a name for the account.
Select Save and Close.
After that, you can use the journal entry feature in QuickBooks Online to post the cash in the AR account and apply the money to your customer's invoice.
Select the Plus icon (+).
Under Other, select Journal Entry.
Enter the transaction date in the Journal date field.
(Optional) Enter a Journal number to help identify the transaction in reports.
On the first distribution line, in the Accounts field, enter any account listed in the Chart of Accounts.
Enter the transaction amount in the Debits or Credits column.
Specify a customer, vendor, or employee associated with the line, if any, in the Name field. Note: QuickBooks Online Plus and Advanced users - When the Classes and Locations feature is turned on, additional fields for Class and Location appears.
Continue to enter distribution lines until the sum of the Debit column entries equals the sum of the Credit column entries.