Congratulations on your successful campaign.

"Congratulations!" is the correct word here. If you are talking in person and the achievement has already been mentioned, then you can just say "Congratulations!" In writing, or if you are the person speaking first, "Congratulations on [your achievement]." You would only say more than that if you were closely involved in the achievement, in this case if you had been following the campaign closely and knew all the details.

Congratulations