MSC Cruises oh dear, they are not great or at least this cruise wasn't.
Booked flights separately and flew in to Treviso, quite simple to get to Venice Port, catch the bus to Venice (Piazzo de Roma) then the Sky Shuttle to the port (1 euro) or you could walk instead of the Sky Shuttle about 10-15 mins.
Service is pretty horrendous, staff look miserable but then again I am not surprised the way they seem to be treated.