Sorry for misreading. Each of the companies I applied to were through general email@example.com
email addresses. I have no way of following up short of resubmitting my portfolio, or finding a general phone number for each of the companies as suggested in the article. I will try the latter before remaking my portfolio.
I feel that I am as equally proficient in 3ds Max as I am in Zbrush, and that I follow a typical game development work flow on most of my models. If my portfolio isn't conveying that, then I need to change it.