Advice on Orange mobile phone contract cancellation

Apologies if you've been through this before but it's my first post. I have an 18 month Orange mobile contract with 8 months to run. My wife and I are about to move to South East Asia (8 months earlier than expected) and I phoned Orange to see what options I had available, to which the Customer "Service" Advisor basically told me it was tough and that I'd have to pay the remaining bill (over £500!), that despite me being a high usage customer for over 10 years. Has anyone else had experience in this area and can you offer advice on ways of reducing this bill, or any other more palatable options available?