Vodacom Insurance a dismal failure and no respect for clients

The misalignment between Vodacom and its insurance company is a big failure especially when coming to handling clients claims queries. I lost my phone on the 8th July 2018, today is the 31 July 2018. The claim was approved, however Vodacom tells me that they have under-insured my device and before processing the "approved" claim I must back pay the difference of the insurance cover. When they upgraded my phone from iPhone 6s to Samsung S9+ they made no mention, let alone advise to match the insurance cover to the value of the device. However, when asking them to calculate the difference I am now being moved between "Policy admin" and "claims" departments. On the vodacom pricing list a Samsung S9+ costs R 18,149 and iPhone 8+ costs R18,299 but apparently the iPhone 8+ is a "No" because it's "too expensive" even though I offered to pay the difference and get the policy premium difference covered. How else can one really deal with these inefficiencies? Vodacom as a company, why don't they just leave insurance to insurance companies and stop being greedy while failing and causing customer frustrations...…..? It's actually pathetic and disgusting to be put through so much troubles just to claim what is rightfully mine, I am not asking for freebies.