what do i do when my checks are being garnished for an apartment i never had?

A writ of execution or writ of garnishment will only issue in Nevada after there is a lawful Judgment entered against you.  Once Judgment is entered (or domesticated), in Nevada you are to be served with a notice of the Writ of Execution pursuant to NRS 21.075 (Notice of writ of execution: Service required; form; contents)  This notice would advise you of a process by which you can contest the execution or assert any exemptions of property.  The Court would then conduct a hearing on whether the execution/garnishment was appropriate.