The girls 9in6 tiling problem

Can someone explain this better for me.

What I’ve caught is the girls instructed the tiler to follow the previous tiling method.

9in6 stopped the tiler as the distances between tiling was inconsistent and causing a problem.

9in6 offered to pay for the days tiling work.

If the tilers work was such a defect that 9in6 had to call it off, why is anyone paying for the work at all?