MTN Committing ***** when billing

I have a contract with MTN and insurance for 2 phones, in May they charged me extra R300+ when I asked why they told me I have been charged 4 times for one of the phones by the insurance however they can't help me so I have to call their insurance when I called their insurance they don't know what happened but they will investigate and escalate it.

A month after still no feedback and they debit extra again, when I called to ask same story 4 times for 1 phone, however they still don't know know how it happened and they can't transfer my call to the billing department to find out they can only send send an email on their side.

I then went to reverse the money paid for the phone only and then cancel the insurance because I realized it's going to keep on happening.

3rd month they debit the money I reversed telling me I owe them then I ask them what is it that am owing because you charging me extra and no one knows how or why, then the lady I spoke to tells me I am charged extra because I added an extra phone on the insurance on the 9th of May.

Now this is different from what I was being told May and June, from 1 phone charged 4 times to an additional phone to my profile but still they can't explain it, worse part they telling me they can't see who was the agent who added it which to me is all ***** because this means an agent can mess up with client's profiles because they won't be known.

This is bad on my side as reversing the money affects my credit and they keep on telling me they going to investigate but nothing happens.

This is month 4 till today I don't have any feedback.

Sad thing is I last claimed in 2016 yet this year they decide to do me like this.

MTN takes action when their insurance complains about the clients but when a client complains about the insurance they tell you they not getting involved you should talk to insurance yourself.