Literary agent help, Email Queries?

a short time ago, i wrote Mr.Daniel Lazar about a novel id wrote. he asked for the full manuscript. i sent it email as he'd asked. Stephen Barr his assistant wrote me a simple rejection, that led me to believe that i'd A. waited too long to send it to them after their request B. didn't write requested materials anywhere on the submission, or C. i didn't submit properly. every writer that has wrote to the agency insisted that Daniel Lazar or Mr Barr, would give impute on their rejections... how do you submit an email query the correct way. by attachment?