1. Jobs are often posted for a short time for legal reasons even though the hiring manager already has a candidate in mind or an internal promotion. Resumes submitted for these jobs are discarded or “kept on file” but not usually acknowledged.
2. Submitted resumes are batch processed, segmented into “review further,” “keep for another role” or even “show to Mary as they went to the same school.” Rarely are a group of resumes sorted out as “NO” at one single time, which makes it difficult for any one individual to be assigned accountability for notifying candidates that they are no longer being considered. Sadly, even if you call in to find out what happened, there may not be a single individual who knows where exactly you landed in the process or why.
You can still make a call and you may get a real answer- its worth the effort. You are certainly owed an answer on the grounds of common humanity, it's worth reminding a busy human resources office of that.