Are you using AdWords Express or AdWords?
Also, when you say you paid your bill but your ads are not running... how long ago did you pay it? It may take 24 hours for activity to resume.
If you feel there is something wrong with your account, you can contact AdWords Express Support and they can access your account with you and take a look. Call 1-866-246-6453 Monday-Friday, 9:00 am to 8:00 pm (EST).
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