well, not if according to the license of the purchase, she was allowed to make derivate works AND commercial use. Though I'm not sure about that Usually when you purchase stock, you are allowed to commercial use. Sounds odd to buy stock and not be able to sell derivate works!
then it would have been correct to tell her commercial use was not allowed, and she would have disabled the prints, since she's a very good person There was no need for those angry comments, telling her she couldn't even upload derivate works to dA and reporting her. But that doesn't matter anymore, since it has all been solved and it's alright now