Incompetant installation of ceilings

We had 140m2 of PVC ceiling installed by the company and just after 3 months every thing fell down it could have been fatal and injured 1 or all off my 4 children and me and my husband or the lady that work for us as it fell down in our laundry bedrooms etc. Now they say it is not there problem and don't want to fix it. I got a couple of opinions that also stated that the PVC ceiling wouldn't have fallen down if the installation was done properly.<br> <br> Kind regards<br> <br> Jolandi