Health Insurance Benefits Terminating

One year ago, while working at my previous place of employment, I contracted an illness (unrelated to the employment). For the past year, I have not worked and have had my treatment covered by the company. Two days ago I received a letter which said that since I have been "inactive" for one year, I could no longer receive health insurance benefits, effective 15 days from the date of the letter. I would have to apply for health insurance through COBRA, which I would have to pay for.
My union handbook says that the company cannot terminate me until after I have been disabled for two years (I have only been disabled for 1 year now). The union handbook is denominated (on the cover) as a "contract" between the company and the union. My employee handbook from from the company also indicates that the company cannot do what it is trying to do. Here, the company is not firing me. They are characterizing me as having been "inactive" when I should be characterized as "disabled." As a result I am being denied health insurance. I am in a rural area that likely does not have lawyers who are specialists in employment law. Do you have any advice?