Can renters sue a contractor?

[Marty Gangler]

I have a rental house that has had some water issues. Sewer back-ups and gound water in the basement. I've immediately come and cleaned anything up for the renters but it has happened just too many times and I hired a plumber to do some costly repairs. I gave the renters a $500 rent deduction for the water issues as they were very upset over things and I wanted to keep the peace. Now, the plumber situaiotn has taken a few days longer than anticipated and there has been dust on the renter's belongings and they claim damage to some property. So they wanted money off on the rent due to the plumbers haphazzard schedule and dust issues (they were informed about the dust possibility - this is an even longer story) I told them I would not be giving them any more off the rent as I didn't have to do it in the first place. They claim they were able to use 1/2 the house - but it was only for 1 week. They have asked for the plumbers insurance info now that I will not be giving them anything. Do I have any liability here? Can they go after the plumber? I don't think they can prove any real damage to anything - a TV (and other things) shouldn't get dusty yet it's not broken. Should I give them the insurance info? Am I at risk of anything? Especially after I already gave them money off of rent for this whole issue. I think they will have a tough time claiming real damage but I don't feel like going to court.

Thanks,