Not updating insurance

I upgraded from a Samsung Galaxy S5 to a Samsung 7 Edge at MTN Maverick in Table View in January 2017. On the day of signing my new contract, I filled in and signed an insurance form for my new Samsung 7 Edge. My phone broke 2 weeks ago but when I submitted my claim form, I was told by MTN insurance that I have been paying insurance on my S5 for the last 15 months and that the Maverick MTN store in Table View had never submitted and updated my insurance for the new phone. This means I have been paying for insurance for my previous phone that I am not even using. When I contacted the store in Table View, they informed me that I was the second client that this specific sales person had done this to. I requested for my signed documents to be forwarded to me. To my astonishment, they claim that they don't have the form I completed for the MTN insurance for my Samsung 7 Edge. Now they also claim they are not responsible for the error. Absolutely shocking! I have been an MTN client for the last 19 years. I always update my insurance on the day of signing my new contract.