No luck finding Birth mom

I just got word that my adoption search has come to an end, at least for now. The man who was doing my search failed to find a current address for my birth mom. He found two recent addresses but with no luck. He works for the agency I was adopted from so I figure he'd be the best bet. I also don't have any names, birth dates or any other information besides medical. It's really frustrating having waited for months only to be told "sorry, can't find her". It was definately not one of the responses I was expecting. I'm terribly dissapointed but I don't know what else I can do. Just felt like sharing...thanks for listening! Liza