First the lession - pick the middle quote and dont pay them until your
satisfied!!

If the turfs only been down two weeks you could lift it (roll it into
the original strips), sort the soil out (dig/pick the stones out, add
top soil) and relay the turf.

You'll end up doing the job you've paid someone to do yourself but at
least it be right.

Whats the quality of the turf like.

Good luck.

Nick