Difficult Landlord with a problem building in McKinney,TX

I am quite frustrated with my office building landlord. We have just signed a long lease on a brand 'new building' which was built last year. Shortly after we moved in, we found several roof leaks (when it rains, you can hear it dripping. We had to place trash bins under several areas in the office to catch the water. In addition, we had plumbing problems (twice).Adding to our frustration, they sent us the plumbing bill for more than $900 (for the 2nd incident) and their own plumber can't find the source of the clog but to say it must come from our office space! We have trying to be patient and try to resolve this but they try not to take any responsibilities for the crappy plumbing they have. Is there place I can file a complaint to? One of the landlord is an arrogant A_ _ and he is some well known politician in another town. He is such a bully. We are so tired of getting them to fix their problems and ended up getting the bill! Please give us some advices as how to deal with these people.

Have a professional review what really has happened--if you are correct then based on what you say here, you could file suit against him (or at least threaten to do so) in small claims court or in regular court; filing in small claims court is easier and requires no attorney...you could try to collect all of the costs and damages that you suffered due to his behavior...