Prudent decision going with a powercat versus sailing.
I am SURPRISED you incurred a cancellation fee. I would kindly request a refund as the company should not have chartered a sailing vessel to you without any previous sailing experience. I would say that is an error on their behalf.
If they insist on charging you for this error, it certainly isn't a company I would care to use as a charterer or a boat owner as they are not properly vetting their customers.
If they do not refund you, please share the name of the company!