She committed fraud, because she lied about a material, or important, thing (that she was donating money to help a girl who had cancer) that would have been part of people's decision whether to buy or not. Lying about something important to get people to buy from you is fraud and is illegal. You could potentially report her to the authorities (e.g. the police; the state attorney general's office) for her fraud, and anyone who bought from her could sue for the return of their money or other compensation.