MTN Negligence

On the 2nd of Dec at the MTN N1 City shop, i upgraded my device (iphone 6s) to a iPhone X. I advised the lady that assisted me i want to insure the new device. A week or 2 ago, i started having issues with my device (the LCD) and i took it to shop, i was told the warranty would not kick in as the back screen has cracked, and was advised to claim via insurance as i have it and they will fix the crack. I called insurance and to my surprise i was told that they have the old phone on their system. I was told that i needed to call the insurance and update the device. This was not communicated to me by their sales consultant at N1 City. I went to the store where a Daniel emailed insurance instructed by the store manager to layout my case, and Pinnacle Marketing responded that i need to write to a motivation and advise that i was never told to call insurance to update the device. The insurance has declined my claim and now i am stuck with a phone with problematic LCD.