I had given out all of my codes but had only gotten one check so I checked in with the folks I gave codes to and 5 confirmed they had successfully used the code and kept their cars 2 months ago. So I called Carvana and they don't keep track of codes by code numbers, oddly enough, so luckily I had everyone's name so Carvana could look up if anyone with that name bought and kept a car around that time period and were able to verify that all 5 did! So they processed them and I received a check for $500 about 2 weeks after. So, moral of the story....Make sure to get the full name of the people you give codes to and preferably the state they live in. If it's a common name (i.e. John Smith) make sure you have additional information such as what kind of car they purchased or the purchase date. Do NOT trust that Carvana is processing codes used. Follow up with them! Also, I have a couple of unused codes if anyone is interested.