I've done a dozen FOIA requests over the years, some very successful, others not yielding much. You may hear response times are "years," but I've often seen "months." I've learned it can be much more effective to submit a request for MAC documents via the CMS office, because it may be dealt with too casually at the MAC itself. ("We got nothin', go away.")
I've always submitted FOIA requests via email with a short request letter attached. Find the CMS home page here:
There's also a FOIA "Reading room," where requests are logged by month. (CMS gets hundreds.)
And a FOIA portal,
Your FOIA request will be logged and you'll get an email tracking number within a few days (if not, something is wrong). Like, say, a Fedex letter, your tracking number allows you to see the case status online.
Find it here:
If you choose to file by form, rather than email and PDF, there are about a dozen fields (name, city, etc) and the request text box goes to 10,000 characters (probably around 2000 words).
I recently requested a MAC document, and got a prompt letter (30 days) that I couldn't have it. I then requested the same MAC document via the FOIA central office. In a few months, I got a letter that CMS FOIA has the document, it is 4 pages long, and they are holding it as a "business secret" (one of the rules for not releasing things.) I had 90 days to file an appeal, which curiously goes to the deputy director of CMS - which I did. Just an example of the process at work.