I don't know if it works the same way there as it does here, but if it does try one or both of these:
1. Give the landlord a written complaint signed by all of you. Give him 30 days to comply or you will start fixing things yourself and hold the costs out of your rent. Mail it to him via certified mail, return receipt requested (so he can't say he never got it). -- This usually gets the job done in the US. If he doesn't then you'd have a better leg to stand on in court and he won't be able to kick you all out without going through eviction proceedings (usually takes 6 months in the US).
2. You can call in a building/housing code inspector to evaluate the property. If it fails the inspection, the inspector will give notice to the landlord that he has a certain number of days to fix the problems.
Again, don't know if your tenancy laws are the same there, but these are our best options here.
You could also call an attorney for advice. Some here will give you a 'free consultation' to see if you have a case.
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The day we stop learning is the day we start dying!(c)
Owner/operator of the Evil Petting Zoo and devout member of the HADB clan.
Mage extraordinair.
Commander of the Dragon Fleet, IW Peacekeeping Force
Occasional subjugate to Gwhanos the Fluffy
Hopeless Romantic *sigh*
"Allright! We'll call it a draw."