http://or-in.facebookwkhpilnemxj7asaniu7vnjjbiltxjqhye3mhbshg7kx5tfyd.onion/business/help/1026272311098874
Closing an ad account doesn't delete the ad account from your business portfolio. A closed ad account still counts toward your ad account limit. If you reach either of the first 2 ad account limits noted above, you’ll need to remove yourself or have someone with full control of the business portfolio remove your access to any ad accounts you no longer use.