Consumer's Energy MI Put someone else's delinquent bill onto my account?? Internet

In September of 2010 I received a notice from "Consumers Transfer Department" indicating I had a delinquent balance from a previous address in the amount of approx $600.  For my "convenience" they would add this amount to my current account!!  Here's the catch - I never lived at the address during the specified time frame; nor was I ever responsible for gas charges until I moved into my current rental!

After MONTHS of trying get this removed from my bill - I have had to send them copies of both of my leases from the passed two places I have lived.  I have had to do this on several occassions - and they still have not removed anything.  I have now reported Consumers Energy to the Michigan Public Service Commission as well as an attorney. 

Any thoughts on what else I can do?  Consumer's keeps telling me that they will remove this amount as soon as they can confirm where I lived - though I've sent them the copies of my leases - my tenant ledgers, etc - and they claim even though that's all I have to do...they aren't removing it "yet."  It's beyond ridiculous and it's really hard to keep up on a bill that I DON'T OWE!!!