Excuses not to pay warranty

My geyser burst in Sept 2024, and the insurer appointed Heat Tech to instal a new geyser. 5 months later, the geyser is over heating and leaking. I then switched it off. The plumber appointed by Heat Tech comes around, they switch on the geyser and see a spark and then leave. They then write a report that the issue with the geyser is caused by an electrical fault, which is not true. I have been calling both Ariston and the service provider Oxyros and they are taking me from pillar to post. Please stay away from both of these service providers.