Account isn't active because you haven't entered your billing information

[Business Drivers]

At the top of our Team's Campaign page in Google Adwords we see the
following Alert in RED:
"Your account isn't active because you haven't entered your billing
information.
To activate your account and start running your ads, enter your
billing information. Learn how."

The student guide asks us not to enter any billing details to get the
$200.
We have been credited with $200 in the 'Billing summary' link under
the 'Billing' tab in AdWords.
But our Ads are not shown inspite of having the status as eligible. We
suspect it is due to the Billing error that is displayed at the top of
our AdWords screen.
Please help us out. We want to get our campaign running as early as
possible.

Thanks,
Team Business Drivers