Not Receiving Hard Bounces

Not Receiving Hard Bounces

I sent out a bulk mail via the contacts tab.  I filtered to a specific criteria, assigned an email from Email Templates, and then sent out ~300 emails.  I received a good amount of soft bounces (auto-replys), but I did not receive a single notification of hard bounces.  

I know I should have received some because I tested out 5 emails address which I knew would generate a hard bounce.  Is there a setting I need to enable to receive hard bounces?  Is there a different way of sending out emails through CRM to see what emails come back with hard bounces?  Is this a bug? Is there a better way to accomplish my goal?  

Goal: I inherited a set of Accounts and associated contracts.  Besides attempting to connect with/market to my list of contacts, my secondary goal is to clean out the database of dead contacts.  I feel like hard bounces would be a great starting point as that would generate a clear list of problem areas.