Franke Group poor quality gyser and bad customer service

In May 2016 I had a new 150l Franke Gyser installed in my home. The Gyser burst in 2018 and had to be replaced and now the Gyser has burst again and has water streaming out of the geyser non-stop and after reporting the fault with Franke no one has come out to fix or replace the Gyser which is still under warranty until August 2020 this year. After having called them, I’ve been contacting them via email and Facebook and they just not responding to an urgent fault. I have water leaking onto my ceiling and causing damage. No technician has contacted me from Franke to come and replace the Gyser. I see on Hellopeter they’ve had similar complaints about their gysers but don’t respond. Warranty claim reference number : ***