David's first suggestion is the best place to start.
If that does not get you an Activation Key, please contact Customer Service at info@wolfram.com or 217-398-5151. They give out Activation Keys.
If the Activation Key does not work, or there is a problem with the returned password, that is the time to contact Technical Support (support@wolfram.com, 217-398-6500).
Sorry you are having this difficulty.