a client has called in panic. they tell you quickbooks online isn't working correctly. The sales by customer summary report and the total sales income within the profit & loss report do not agree. why could this be?

1-the profit & loss report includes credit memos for returned goods, but Sales by Customer report does not

2-the sales report includes donated inventory and this has not been reflected in the P&l report

3-bad debts have been written offusing a customer credit memo and assigned to a Bad Debt expense

4-The client has created a customer invoice to a business that also happens to be one of his suppliers