How many years experience do you have? Was this job basic keypunching or do you need other skills as well? I know when I am hiring, I look for experienced help (minimum 7 years) with knowledge of coding and A/R management. Biling has stepped up a notch from days gone by and knowledge of how EMRs, Electronic Billing and Remittances work helps a lot as well. In addition, be communicative and let the potential employer know you work the phones. Billing requires lots of phone work to insurance companies, patients, physician offices, etc...Do not give up and do not stop calling potential employers. Trust me, I get inundated with calls and interruptions during the day and forget to call people back at times. (More often than not...I am afraid) I LIKE when people follow up. It is less pressure on me. I always make it a point to respond to a resume, however. I would not want to know someone is stressing over a response. Also, even if your interview went well...there might have been someone looking for less money with more experience - so do not sit and wait for this one job. Send as many resumes as you can and follow-up!!! You know your strengths. Market them. It will be worth the wait.
Best of luck.