LVT, pins coming through the floor

sophlouwhit

Had some lvt fitted 1 March 2024, it come with a warrenty for floor and fitting -
anyways move to now and they have been back twice to fix pins coming through the floor, second fix solution was to remove these pins totally in effected tiles, this was done 27 Aug 2024. Since then had 3 more new tiles with issue and raised it where they have tried to blame now subfloor movement for this issue and said there is no issue in hall but is lounge due to subfloor.
For context - hall had a new subfloor laid prior to lvt install due to really old damage which was more freak event then issue with house (to be blunt we bought place where someone had died and builders think this 6ft worn through subfloor wos cause of a person being left dead ) 
the hall has a new subfloor,6mm ply, lvt no issues.
the lounge which has issues has the following layers: old subfloor,ply,old lvt, 6mm ply, new lvt. It was advised to lay new lvt over this as it would stop ridges and we went along with this.
this is the only differences between the rooms.

anyway- im not sure they will fix this again and wondered what exactly i can do about this if anything? With time frame based…
thanks

sophlouwhit

Bump due to retitled

fisher66

Surely the fitters responsibility to ensure the sub floor was suitable. If they gave a warranty then they should come back and sort it, even if that means removing the LVT and sorting the sub floor. Getting them to honour it may be tricky but you have to try. Leaving the old LVT layer and covering it with ply seems odd to me and maybe a bit of a bodge. I would have thought it should have been taken up but I'm no LVT expert.