Creaky floor in kitchen

What is "merried"? Thanks for clarification on what you meant. Firstly I am concerned that you think you should call back the floor fitter to rectify a squeek for free, or even sue him. The floor has been down for 6 years which is a fair amount of time, in my opinion its hardly his fault, especially because it sounds like an issue with levelling or sub-floor movement . Secondly, without seeing photos I van really comment as to why its squeeking. Is it a laminate floor, the tyoe that all click together? I'm assuming an underlay was installed before the laminate- if not then that's bad practice by the fitter, and that's probably your solution. If the floorboards/concrete/wooden joists are moving then it's a bigger issue. Either way the solution will be to take up the laminate (if laminate is what you have?). Sometimes you can remove laminate and relay it, but without seeing the room im not sure that would be possible for you..... Finally, if it is laminate you've got then I wouldn't recommend that in a kitchen, the tiniest bit of water and it's destroyed. If you're taking the flooring up I'd recommend tiling or self levelling and the glue-down LVT

The fact that you even mentioned the idea of sueing someone and are blaming the tradesman for something 6 years later, will not get you very many responses. This is extremely concerning that you think this way. Things move around, especially wood. Changes in temperature and humidity throughout the seasons cause expansion and contraction. It is something that you need a professional to take a look at ideally. Certain things can't be diagnosed over messages and this is one of those things. I Hope this helps.