To report any issues found within the data please find the detail page for that data set/feed. This can easily be done using the data set/feed ID. Browse for that data and provide feedback to the data publisher. This will enable them to read your comments and response to your query. This way data quality can be iteratively improved within the service, and the transport ecosystem.
Contact firstname.lastname@example.org for technical queries if not answered within the developer documentation. As well as to provide any constructive feedback about the service.