We came up against the same with Azamara for our August cruise. Because Ravenna had become the disembarkation port before we booked, Azamara’s position is that we would have been aware of this so it would be our own responsibility to make our own arrangements. As our flights have been arranged as a package Az are charging us for the transfer from Ravenna to Marco Polo airport, Venice. For some reason, they’re only charging what it would have cost to go from Venice port to the airport - €55 pp.