After researching this and taking everyone's advice into account, I uploaded the 1099-K as "Other" and then made two negative entries for the gross amount[s] of both the laptop / printer, stating they were refunded and what they were. I have all the documentation in case they ask. The vacuum was received as a gift several years ago, and thus is considered a gain from selling personal items. Can I claim the shipping (part of the gross payment, buyer paid exact calculated shipping) as a negative entry also, even though I'm not a business and thus not filing a schedule C?
