Overcharged with no details on account

I was at work- water ran from overflow pipe. Plumbing lady daid it was “burst geyser” , and geyser must be replaced. I received an enormous (once off amount), account. I tequested “plumbing lady to review and give set out detailed account. I did not receive it. Overcharged services that no proof or detail can be given. I was told that I will teceive a “ guarentee” of geyser, she will leave it. After enquery: I was told to find & look up the guarentee on the website , if I need it Be careful for chancers, overcharged services !!