Dangerous geyser installation by AWS

AWS Installed a new geyser when ours burst. Their plumber did the installation and it was not compliant. When I asked them to send a new plumber (they fired the last one) they did but refused to approve the quote - although they had admitted their error and committed to repairs. The manager Mark blocked my called and did not answer my email or messages over a month period. I then contact his wife who is the owner of the company. She said she would help when they hired a new plumber. Then then blocked me and when I called her on another line she said she would no longer finish the job because I had asked the plumber to share the quote with me. Her words when I threatened to go to the small claims court: 'go for it'. Another plumber has confirmed the the installation AWS did is non-compliant and dangerous.