I think the problem is that the 1099-MISC is not proof of what you actually did, it's only proof of the amount you were paid. You may need to document how and why you were paid that money--for example, that you were an appliance sales person on regular salary from the appliance store. That you sold an unusual number of appliances or you sold some unusually expensive appliances. Do you have other business records from the appliance store? Do you have copies of paperwork that was submitted to the manufacturer, or statements from the manufacturer, showing the appliances sold, the date, and the amount of incentive? Can you tie those statements to other business records from the store? Did you keep a separate diary showing what appliances you sold, on which dates, and when the incentives were paid and the amounts?
You don't just need the 1099, you need to build a picture for the investigators of what you sold, when you sold it, and how you qualified for the incentives.
And you need professional representation.
