Contests are weird (and usually not very satisfying) so this may not work- but if she put up prizes, she needs to compensate for the value of the prize and actually she either needs to ship back your 'inferior' supplies or compensate for those as well.

Also when your transaction is finished, wash your hands of them and possibly write a beware. They are not acting professionally or with courtesy to your, especially as you took time to participate in their contest in the first place.