cannot change credit card info after moved to other country

Do you have a credit card in Canada registered to a physical address in Canada? If you do, did you go to Settings>iTunes and App Stores>Apple ID. Tap your ID. Tap View Apple ID. Enter your password. Go to Payment Information and try to change the card in there?

I'm assuming that you are refering to your itunes account. If you are acessing the Canada itunes store, then you must have a credit card on file with your Canadian address. Have you changed the country setting?

To change the itunes store's country...

1. Tap "Settings"

2. Tap "iTunes & App Stores"

3. Tap on your Apple ID

4.Tap "View Apple ID"

5. Enter your user name and password.

6. Tap "Country/Region."

7. Tap "Change Country/Region"

8. Select the region where you are located.

9. Tap "Done".

this is what I did but when i select "change the country" Nothing happen... what am I supposed to do ?