Can you cancel an order as seller? Buyer says they didnt want to bid the amount they won for

[mountmini]

I have a buyer who claims she unintentionally had a bid that won. Shes says....she looked and wasnt the high bidder, and then all of a sudden she was.

Whatever, it didnt make much sense. She wants to cancel now.

I just want to know if you can cancel orders? Or would that affect my selling ranks by cancelling orders?

Thanks