Steibel Eltron Instant Water Heater

I'm really not impressed with the quality of the Steibel Eltron Instant Water heater. Three years (April 2017) ago my original Seimans Water Heater, which had lasted 14 yrs, was replaced by a similar Steibel Eltron unit as the Siemens one was no longer available in SA. After just three and a half years (October 2020) usage I've had to replace that Steibel Eltron unit with a new one at a cost of around R 9500 fitted !! To me this is totally unacceptable quality and reliability, but was told there are no alternative makes !!!