I have booked interline travel on many occasions with vacations to go. Most recently I booked a 10 day cruise on Princess cruises. I asked to add the Princess Plus and they said they were unable to do this. The very next day I saw the same cruise on Perx and called and they could book the cruise cheaper and they were able to add the package we wanted. VTG has terrible customer service. I've contacted them, including supervisors several times with no resolution.