limitations on medical bills( Medicare)

[58Chrysler]

What is the name of your state?
Michigan
I need to know what, if any statute of limitations on medical bills( Dr office, not hospital)
I just received an initial notice from a collection agency regarding some small medical bills, from 2 to 4 yrs old, that I knew nothing about until this notice.!

I have a pretty good idea what's going on here, and it stems from the utter incompetence and laziness of my previous dr's billing people, and the overload/slowness of the Medicare payment in that area( I relocated in 2005, to central MI. And yes, I filed a change of address with USPS, and the dr's office had my new contact info.)

It is not a large sum of money( a little over $300), but I am just completely fed up with having to pay old medical bills that should have been paid by insurance had they been properly coded and submitted!

How should I word my dispute response to the Collection agency? Can I demand that I be given complete details of each bill, so that I can research with Medicare and my other insurance whether or not the bills were even submitted??
Cindy OWhat is the name of your state?