How should I get my security deposit back?

As long as you gave the Landlord notice of your new address, you may have a counter claim against them. Michigan law requires the landlord give a statement to the former tenant within 30 days of moving out. How the landlord handled the security deposit can also open them to additional claims. If you live in the tri-county area I would very much be willing to take this on, if not, I invite you to call to learn what your rights are at no charge.