What can they legally do?

I designed a dress at 17 and got money for it, i had a work authorization permit, the condition of me getting the money was i had to be a legal resident, and I said I was. They now asked me for doentation that i was a legal resident (im 19 now and have my green card) is having that work permit count as me being a legal resident at the time?? can they omit my payment because of this?? nobody checked until now and i received the payment 2 yrs ago.