The best thing to do is to upgrade the account to the next level. To upgrade, please sign into your account and click on the “Upgrade” link on your Account Dashboard, located towards the upper right of the page. Alternatively, you can upgrade by clicking on the ‘Subscription’ link at the top of the page and selecting the ‘Change Plan’ tab. Please see ‘How do I upgrade or change my subscription plan?’
Alternatively, you can opt to archive the campaigns that you don’t need to track anymore. Archived campaigns are considered inactive and do not count towards the number of campaigns limit on your account.
Note, however, that once you reach or go over the limit, you will not only not be able to create new campaigns, but you will also not be able to restore any of the archived campaigns.