I did a joinery job before xmas (finished 6th december) for a local shop,there rear storeroom floor was rotten,someone had replaced 9 joists in the past but not properly,so i quoted to remove existing flooring( i was to discover 6 layers in places to strengthen floor
) remove and refit solid joists already fitted and replace 12no rotten originals,this also entailed removing/rebuild a studwork cloakroom as the floor etc ran underneath,i did this and and discovered a broken toilet pan so informed client (they said they would deal with toilet etc) i completed job and invited them (or an independant person) to inspect my work,they declined both and paid me,im a regular customer in the shop so have asked many times if all is ok and the reply is always "its great"......i get a phonecall on saturday from the female shop owner saying that a plumber had come to fit a new toilet but he was saying the floor is too low and the drains would have to be lowered ie not cheap,she phones me ranting and raving that its down to me etc! i pop in afetr speaking to a plumber friend who says its not uncommon and you just build a small plinth for the toilet to sit on (or plywood cut to pan shape), she seems happy and will speak to plumber to ask what the height difference is,she then phones me yesterday ranting again that the plumber returned with a joiner who says the new bathroom floor is unsafe! and its upto me to fix and she wants it done now! ,but she cant tell me why its unsafe? and seemily 2 joiners have said the same but she cant tell me why! im going to have a look at the floor but i constructed the whole floor the same way..........any advice on how i stand,im more than willing modify it within reason but she has waited 3 months to raise this point 
Im a little concerned as to how i stand on this matter, sorry for the long story everyone.
Many thanks for any words of wisdom
Joe
I would not take a great deal of notice, execept, on your next visit, get lot's of photo's, 
if? they turn nasty, 
,told her to calm down and explain whats been said......it turns out,that apart fro my oversight on 2 support trimmers the main problem is the open staircase to the cellar (with balustrades all round),they agreed to it at the time,although now cant remember doing so 
and they want a flat hatch cover,ive agreed to change it as all materials are on site anyway and to keep the peace.........and 2 joists that someone has said are'nt on the foundation enough although they are)which im going to sister up the end 24"approx with 8x2"'s bolted through to please the woman.
....women!