I DON'T OWE YOU MONEY!!!!!!

I had left Fedhealth more than a year ago, I paid the balance owed to the scheme. A month ago, I received an SMS to say I was being handed over to a debt collector for the amount I had already paid. I contacted Fedhealth call center who assisted me and confirmed that I do not owe Fedhealth any fees. They sent me a tax certificate to confirm this. Again this morning, I relieved another email saying I still owe them this money and that I would be handed over. I just don't know who to call or what to do anymore. The "Heather"the SMS says I should call does not answer my calls or return my messages. I called again this morning, for the credit controller to confirm once again that I do not owe them money, and that I should just ignore the SMS's threatening to hand me over. - ABSOLUTELY CREDULOUS!!!! I regret ever joining Fedhealth, I would not recommend joining this company because they cant seem to get something as simple as cancelling your scheme right, don't let them manage your medical issues.