Have you been granted an interview yet? If so, you could contact the interviewer and ask what it was about your interview that they decided not to go with you.
If you've only just submitted a resume, I'd suggest that you take another look at your resume. You do have experience, but maybe there is something else in your resume that is causing them to not call you. Is your resume clear and easy to read? Any spelling or grammatical errors?
What does the job description say? Do you have those qualifications? If not, they're not going to consider you. Also, since this is a VA hospital, the billing is different. If you weren't aware of that, they may not take the chance to hire you.
Are there even any job postings? Sometimes there are only internal job postings, and you won't be privy to those. If there are public postings, then look at the job description. Using the same language that they do, tailor your resume and cover letter to include those qualifications that you do have--but in their words. This is a trick that sometimes can get you an interview, at the very least.
Make sure you're sending your resume in the correct format to the correct place. If you're sending a hard copy and they want an e-file, I guarantee your hard copy has made it to the shredding bin. Nowadays, most employers need to do all of their recruiting process online, and you don't want it to appear that already you can't follow directions.
If there are no job postings, you can send a million resumes, and you probably won't even be notified. I suggest you get in touch with your local AAPC chapter, attend meetings and see if you can meet someone who already works there. That way you can ask about what the workplace is like, what kinds of jobs are available, what the culture is like and whether or not you have the qualifications to be considered.
Hope this helps.