Its the original number you've linked GV to a USA or DR number?
google voice assigns you a USA number then I linked it to an american number (at the time I had magic jack). So once the number is linked to an american number then you are done. That linked number is of no use now because I pick up my calls via hangouts app. So the linked number is not even activated anymore as I don't have the magicjack unit anymore.
but you can link it to a number of a family member in usa and then just forward all calls to hangouts app. just un-check the american linked number so that person won't get any calls forwarded from your google voice number.
i know it sounds confusing but it's really simple.
I also have a USA number for incoming calls only , from callcentric.com. I have that callcentric account configured on my VOIP box and connected a wireless phone to it. Now when someone calls my google voice number, my cell phone hangouts app and my voip box ring at the same time. I can pick up the call on either one.
AZB