Three comments:
First, you have two listings, so it would've been helpful if you'd mentioned which one was involved in the issue you're asking about.
Second, I notice that neither of your listings charges a cleaning fee. You should *really* consider adding one.
Third, and getting to your question, the $13 service fee that you see in the accounting of the payout from your end is *your* host service fee of 3%, not the guest's service fee. Their fee is likely to be 10-12%. That said, even if it was the full 12%, their charge would be around $470 USD, not the $538 that you mention. Might this be a currency-exchange issue? That is, is your guest booking from another country that uses the $ sign for their currency? (Australia, Canada, etc)