Sorry that this happened to you, but well, people kinda really have to learn to inform themselves about that stuff before taking action...
They provided a site with all the information you need about the event and no one was forcing you to spend your tokens immediately. You should read up about that stuff beforehand next time to prevent frustration.
The trade for Lunar Revel Orbs wasn't supposed to be equal, you can just trade golden tokens for them in case a Lunar Revel Orb is dropping a golden token for you and you have no interest in the skin chromas, so to prevent that the golden token is completely wasted for you.
That being said, we can't help you in here. All you can try is to submit a ticket to the support here.
Maybe they can revert the purchase for you and give you back your silver tokens.