Franke not honouring their Warranty - Need to be taken to Task

I installed a Franke Geyser on 12 December 2016. Within 7 months it burst and Franke had a new one installed on 13 July 2017. Last night it burst again. When I called and spoke to Les on *** the person who deals with the Warranty he told me they would send AB Plumbers to check. I was told that the Geyser had burst and they no longer manufacture Geysers so I would receive a settlement of R4250 for my 200L Geyser. It costs R8500 exc VAT to replace. I called Les again and the referred me to his Manager Jayson who did not help me. He said that R4250 s what they will pay. In my view Franke still exists and should honour their Warranty by replacing my 200L Geyser. I have called my Insurance company AON for advice and will go the legal route to take Franke to task. Anyone else had a problem with this careless company called Franke