BREACH OF CONTRACT

I had a Frankie Geyser burst on the 12 May 2011 and the Frankie Geyser was installed but 2years later October 2013 it gave me problems and was again replaced after numerous complaints as they didn't want to take responsibilities as it was still under Warranty but now again the same Frankie Geyser its heavily leaking and I called on the 11-03-2018 to standard bank insurance then they send the plumbers through fortunate enough the geyser is still under warrant as it takes 5years but now they say I must pay an excess of R750 how can I pay whereby its still under warranty? it simply tells me that Frankie Geysers are not good at all can someone sort this thing out as we cant be having Geysers that they don't even meet the standard duration of their warranty . just now I received a call from the appointed plumbers that the company "Frankie " told them that I must pay R750 why because its still under warranty? can some one urgently sort this out with Frankie Geysers please this is total reap off "DAY LIGHT *******"