i has a problem with an insurance job a few years ago, never even managed to get tiling just ripped a wall down, the customer used my quote to use for the insurance company then employed someone for cheaper, once i got wind of this i phoned and phoned but to no avail. finally a nicely worded letter mentioning insurance fraud and me turning up at her place of work got me some attention. i offered a settlement that she agreed and that was that,
i would go back and sort bad tile then threaten them with legal action if they still refuse to pay,
ask the other trades on the job if they know what insurance company is supposed to be paying maybe one of them will know