Request a refund for invoice *******

Hello there,
 
Mary sent an invoice to pay for a maintenance renewal, I asked the development team and said they still need this service and I wasn’t aware that we already paid for perpetual license, so I paid for it, then the financial team sent me notification that we should have a permanent license and don’t need renewal. I asked Mary to refund the invoice but she said that her hands are tied because she already sent me the keys, we didn’t use them and we have 0 interest for maintenance update and it's unacceptable to refuse refund $1000 we have nothing to use for.