MR Price making insurance into an open and running debt account

I Last made a purchase almost a year ago at Mr Price on my account for R150 (which was payed off) the last while Mr Price have been contacting me telling me that my account is in arrears (which is impossible) I asked them by how much and they told me R800.00. When i queried what it was that I bought they informed me that it was insurance premiums that built up. I then went in to Mr Price and cancelled all my insurances which I was completely unaware of I had. No they are threatening to hand me over for failure to pay. I was informed by Mr Price with the lady on the phone that in a month from when I cancelled the insurances that all the outstanding amounts will also be cancelled but it hasn't happened . I have tried numerous times to phone them and have it sorted out but I keep on getting transferred in circles. I have sent Emails and have received any reply. This is ridiculous!!! My final question is how can an insurance premium become debt and just heap up in to a crazy ammount?????