cancellation of insurance for cellphone

I have been battling to cancel the insurance for cellphone but without success. I have even forgotten the cellphone I insured as it is long back but Markham keep on saying I must provide the papers, this is unfair on my side because they debit the premiums from my Markham account, which is I am paying for nothing. They know the phone that is why they are debiting. Please help me to cancel this cellphone insurance. My account number is ***