Your social security number is required to activate your Green Dot credit card. If you never used a social security number then call 1-866-795-7605 to activate your Card. In the prompt you will hear what number to click to activate your new card. You will need to use the 3 digit code on the card to activate it.
The issue and preferred resolution, in GetHuman-ianboxel's own words:
I went online to activate my greendot card and i cant use it anywhere online. I then called customer support and they said my card number was invalid.
I trust that Green Dot will make this right and come up with a resolution that is fair.
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