Thank you for reaching out about this. Have you checked through the different folders you have set-up for your account and/or within the status area? You can also change the Sort option to locate campaigns:
Please email us at social_support(at)constantcontact(dot)com with more specifics (such as: what type of campaigns are not displaying, what was the status of those campaigns, the date range of the missing campaigns, approximately when you noticed this happened, etc.) if you are still not able to locate all of your campaigns.