What Causes Drop In White Blood Cell Count After Taking Tecfidera?

I have me and have been on Tecfidera. At my neurological appointment a month ago my white count had dropped from 1200 to 500. My Dr was concerned about this as it is a side effect of the drug. Long story short....I have not been able to get any response from my Dr s staff since the latest blood work. I have been told 3times in the last two weeks that someone would be calling me back. Is there a medication that will help me bring these levels back up and how mean do I Need to be to the office staff to get some answers.