Personally, I wouldn't help them. If they didnt for you, then dont for them.
It's like the situation I am in, in my house....the rain keeps coming through the ceiling, and has got to the point where the ceiling has started to fall apart... we rang and rang and rang, they came out once, and it didnt work, so rang and rang and rang....
now we are that fed up we dont ring anymore, if the ceileing caves through it's not our property...we move out for a few weeks whilst its being sorted but ultimately they pay the price for not doing it in the first place.
I would ignore the calls, and ignore everything, because at the end of the day, they can show people round when you have gone - saves you the stress and a job that they should be doing.
Life isnt a practise,you have to get it right first time!