Change the country or region

You need a zero account balance and you need to cancel all your subscriptions. If you have cancelled all subscriptions, but some haven’t expired, contact iTunes Support. You need a credit card issued by a bank in the country the store is in, and you need a billing address in that country. If you have an account balance, either buy something more expensive and pay the balance with a credit card or contact iTunes Support and ask them to zero balance your account.

Purchases - View, change, or cancel your subscriptions

Purchases - Subscriptions not billed through Apple 

Region - Change your iTunes Store, iBooks Store, or App Store country or region

You've tried on both your iOS device(s) and computer's iTunes ? If you have, you could try contacting iTunes Support and see if they can help : http://www.apple.com/support/itunes/ww (click on your country's flag, the country where you live, and which is therefore the country on the account ; click on Contact Support towards the top right ; click on Get Help under 'Talk To Us’)