unauthorised insurance deduction on contract device that was lost & declined by insurer

I have a contract of 299 per month upgraded in August. I did not take any insurance on the device and so expect my premium to remain the same.

I had insurance on a previous device which got lost and the insurance declined the claim on the basis that the phone was not used with the sim on contract since I bought it as a gift. They somehow cancelled that policy even though without talking to me and issued another policy still without talking to me. I went to enquire at mtn shop and they say I should talk to mtn insurance.

I called them and they promised to look for the video confirmation on how the insurance was issued. They also confirmed that there is no new device insured. Apparently they never called back. I had a followup call and was assured that the policy had been cancelled.

Now my problem is mtn keeps wanting to make deductions for insurance which I do not have and as we speak my line is suspended even though I paid for the device and declined to pay for the insurance.

So far nobody has not helped me, the shop refers me to insurance where I am equally not getting help.

How do I rectify this *******. Why should I be paying for insurance which I do not have and which I did not authorise. Anyone who knows how to have this sorted out please assist