Thousand of email stuck Mail Delivery Reports

Hi Guys, well this is my first time using a vps but today i was looking my mail delivery reports and i see thousands of stuck messages on the report all from the same address that doen's exist on my server. can you guys help me? i've edited system mail preferences and set the same address on the three options, but i don't know why this is happening. [removed - use of real domain name] I don't know what to do... Thanks if you can help me guys! 50315