Excess payable on warenteed geyser??

ABSA insurance replace a burst geyser on my property in 2008. On 31 December 2010, this geyser burst and ABSA again replace the unit. Last week we again had a burst geyser and apparently this unit is no longer under warrantee, as the 2008 warrantee app**** (even though the 2010 installed unit had a large sticker on that said 5 year warrantee). Surely a new unit requires a new warrantee? I therefor now had to pay an access fee for the latest replacement ??!!