Double insurance charge

I have been an MTN costomer for 18 years. I have just found out that for the past 17 months that I have been incorrectly charged on my cellphone contract. In December 2016 I upgraded my phone at MTN Melrose arch. I was assisted by Ivan. At renewal of my contract I elected to once again insure the device. Ivan showed me which forms to fill in which I did with his help successfully. I have just found out that for 17 months I have been charged twice for insurance. The insurance on my old device prior to the current one was never cancelled.

I.e When I renewed my contract for a new device the insurance on the old device was not cancelled. I would like to be refunded for the past 17 months. I was never informed that the old policy had to be cancelled and at this time all insurance matters were handled by MTN and as such they are responsible for ensuring this is done or at her very least informing customers that it should be done. It was assumed that when the old contact expires, so does the insurance - if this is not the case, customers must be informed.

The only way I was able to find this out was going into another branch enquiringly about my high bill and being shown on the computer that I was being double billed. This was not displayed to me on my statement which I am sent every month. I am extremely dissatisfied by this treatment and expect MTN to rectify this as soon as possible.