When a record is created or synced, it will be seen in under Sync Reports.
For example, in your "Processed emails from Salesforce to Constant Contact" under the Sync Reports, it says that the specific record firstname.lastname@example.org can't be found in the CRM side by the user.
In some cases, it is created but will be synced to your Salesforce Recycle bin.
So go ahead and check it. If the record is not there then please let our 24/7 Support team know so that we will alert our Logs team to check and review it for you today.