1. Send a note to the property pointing out the error and asking that an appropriate credit be issued.
2. Wait some reasonable period of time, I tend to think 10 days, and if no refund has been initiated, initiate a chargeback. Make certain that your chargeback contains the appropriate documentation clearly demonstrating that the charge was not appropriate, e.g., rate terms showing parking included and then folio showing parking charge. Then note that the property has not issued your requested refund.

Unlikely that this is some sort of plot or conspiracy.