Ontario Energy Savings Corp ,Gas Colections / Bond Street Collections Inc Burlington Ontario

Ontario Energy Savings Corp has sent a fouls claim to the Bond Street Collections Inc. They are claiming I owe them $548.19 for cancelling my contract with them. They tell me as I moved I was automatically cancelling my contract with them. My contract was up in at the end of Oct 2008 and at that time I notified them not to renew my contract as I was going with another broker. The new broker also contacted them thru my bas company to have this change made.

Here is what confuses me: My Bills show that Ontario Energy Savings Corp has been my supplier at the new address till the end of Oct 2008. How as it that they are charging me for cancelling by way of moving when I continued to use them after my move. I moved Dec 05 2007
They have ignored all of these contacts and are going ahead with charging me $548.19 for cancelling. They never contact me regarding them matter rather they sent it to a collections company. I understand this kind of bullying has been used on other as well.

Can anyone help me fight this? I only have 4 days till is shows up on my clean credit rating. I do intend to fight this to the end and have any tarnish that is inflicted on my rating fixed.
Looking for help,

Richard
Burlington, Ontario
Canada