Did you cold-query or did you have connections?
Originally, I cold queried JABberwocky (the agency). I got turned down. I then met Joshua (my agent) at the Nebula awards and he told me to query again. That time, he liked the query and read sample chapters–then rejected those, but told me to submit to him what I wrote next. That happened a number of times, each book getting a rejection–but stronger encouragement that I was getting closer.