Have you registered your phone number with magicjack, not the free phone number issued by them, but the cellpho0ne number you are using?
If not log into your account, using the email address and password that you used when you registered your magicJack.
Once logged in, click on the tab named "International/Prepaid" and enter the telephone number you will be making International calls from and click "Submit". Make sure you enter it into the box associated with the magicJack that you have or will be adding International Prepaid Minutes to. You will receive an email with instructions and access code, 305-848-9999.
Dial the access code to start making International calls from the phone number you registered. Please remember that you can only register one additional number per magicJack.
Note: In order to make International calls you need to purchase International Prepaid Minutes.