There are several resources you can use when none seem to be immediately available: your imagination and intutition.
What might tenants complain about? Noise (music, barking dogs), smells, strange or unpleasant neighbours, shoddy service or continual problems ('My air conditioner's broken - AGAIN!'), for a start. Make a list of complaints stated in unemotive language. You could then assign "shy", "angry", "exaggerating", "won't take no for an answer" kind of roles, if you liked.
There's also the landlord or agent role to think about. What sort of language would they need to apologize, assuage tenets, hedge, or even evade responsibility totally? (Not sure if the last is likely but it could be fun). Also, where are the dialogs taking place? In the tenant's accommodation, or in the agent's office? On the telephone (this would perhaps make students have to focus more on the language)? There are many possibilities here.
Don't forget that getting people to do things ultimately requires tact, often compromize, a polite request or suggestion after letting off a bit of steam! Some ideas on persuading, indirectly requesting etc here:
http://www.eslcafe.com/forums/teacher/v ... =5422#5422
Once you've decided on the language you can start thinking about the methodology (materials, instructions) that you'll need to prepare to make the activity go smoothly.
Actually, I'm not sure how these kind of disputes get addressed or solved (I have been lucky with landlords, I guess)!
You might want to look at more basic roleplays (e.g. hotel room, or restaurant re. the meal, complaints), where there are less complex factors at play, for some ideas of the general outline that these kind of dialogues take (among others: notifying/stating "facts", possible denial and negotitation, resolution etc). I'm not sure in which the complaints might be the more vociferous: hotel and restaurant customers have nothing to lose because they aren't there for the long-term, but long-term tenants are paying a lot more out and could feel so aggrieved that they let their frustration get the better of them.
Generally, "script" theories are helpful. Actors, props, location etc. And talking of scripts, don't be afraid to order retakes or offer "directorly" advice.
