Creation Entertainment Bait & Switch- Switched lineup, refuse to issue refunds CA

In Jan 2018, I purchased a ticket to an Outlander fan event taking place in August. They advertised all three of the lead actors would be present. Two weeks prior to the event, two of the three leads cancelled.  Creation refuses to offer refunds. They brought in lesser know actors and feel this is sufficient. I paid $600 for a unique experience and now won’t get the value. Something needs to be done to stop this unethical practicE.  All I want is a full refund, it shouldn’t be this hard to get.