Who did you book with - T/A or Celebrity direct? Who ever it is call them and speak to them, but if you have cancelled you will have lost your deposit which is a shame as they would/could/should have swapped you onto an alternative cruise. It does clearly state in the T&Cs that flight routes are not direct and not guaranteed. The Glasgow flight may be with a carrier that X do not have a contract with, or may be sold out of their allocation - you should have asked.
As A of N says it is always worth talking to someone before you take drastic action. If you are still able to keep that particular cruise booking you may be able with some astute negotiation to turn it into a "Cruise Only" booking and make your own bookings for flights. transfers and hotel overnight stay, (make sure you do the overnight in an hotel in case of delays) They don't want to lose you ( unless you said something rude to them when you cancelled). .... Neil.
Princess Cruises - Crown Princess - 4 Apr 2017 - 5nts
Rome (Civitavecchia) : Kotor : Corfu : Rome (Civitavecchia)
Now from £489pp
View No Fly Cruises from Southampton >>
Click here to see offer
Princess - Pacific Princess - 26 February 2017 - 22nts
UK : Hong Kong : Sanya : Singapore : Phuket : Cochin : Mumbai : Dubai : UK
Now from £1699pp
Click to View Info Page>>
Princess - Pacific Princess - 07 February 2017 - 24nts
UK : Sydney : Papua New Guinea : Yap : Koahsiung : Hong Kong : UK
Now from £1999pp
Click Here To View More Princess Cruise Deals >>