I still have not received my Michigan tax refund. They requested documents and I sent them. I can't get through the phone service to talk to someone. What should I do?

You can contact the Michigan Taxpayer Advocate Service to see if they can assist you in either finding out the status or tweaking the process.  Tell them the problems you have had and difficulty reaching anyone.

Below is a link to a list of contact numbers at the MI Dept. of Treasury.   Did you use the first number on the list previously--the one that says "Individual Income Tax?"      Scroll WAY down near the bottom of the list, and you'll see  "Taxpayer Advocate" and the phone number.    I would phone.  Don't use the email since email is not secure for tax ID numbers and other sensitive info.

Or did you have a contact number from a letter you received from the MI Dept. of Treasury with the initial problem?    In any case, here's where you can get the Michigan Taxpayer Advocate number;

https://www.michigan.gov/treasury/0,4679,7-121--8483--,00.html