How do you use go phone phone cards?

when I do it online, it says the card isn't valid in my state or doesn't exist. I just bought it. Do I have to do it over the phone? Am I putting in the right #?

How do you use go phone phone cards?
Sometimes the numbers aren't 'enough' for the website to see as a valid number. I usually call the number (from the phone) and let the automated service do all the work. If it still tells you it's invalid, take the card back to the store where you got it and get your $$ back!