Working on DESKTOP - having a hsrd time finding help for QBDT

We occasionally have customers rescind their jobs and have to repay their deposit. Essentially we've taken $XX and posted it to their account as a sales receipt, but then the contract is voided and we issue them a refund for that money. No problem thus far. The refunded (check or CC or finance) is sitting there and needs to be resolved against something??  The boss has had me making an invoice for the amount and paying it, but that artificially inflates our sales income. I saw something that said to enter the sales receipt as a negative, but QB won't accept a negative there. We had the money, we gave back the money - how do we record that so the amount isn't showing up on any reports?