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?

Hi, I am Emily, I was miss-sold a contract by Orange 3 months ago.
I found this website on a mobile forum: www.tariftradingstandards.org.uk
I was skeptical but applied for an application form anyway.
I sent the application form back with £10.00 for admin cost and 4 weeks later
I received £140.00 in cash plus a letter from the company I got the contract
With and they have even lowered my tariff to a cheaper package.