Have a technical question you can't find the answer to in FAQ's? Ask it here. Game problem questions that do NOT pertain to things like training advice, what would my horse do well in, how much is it worth.
I don't think they last forever--- I had a couple hundred, and I know there aren't that many there now... and I know I won some with certain horses, and those aren't there either.
You'll just have to win some more!
**did you sponsor an event and offer a trophy prize? If so, those can come out of the ones you've won, I believe.