Former employer wants rent for storage MI

[kozlovski]

my former employer allowed me to store several items in their building free of charge while i worked there. no money has ever changed hands. Now, six months after i left to work for a competing firm i received a bill for 24 months rent and a utility bill. This bill coincides with the decision of the michigan department of labor decision that they must pay out the vacation time that i had earned. Do they have any recourse?