Apartment refuses to fix plumbing problem. What do i do?

I've lived in my apt. about 2 years and been having this weird problem with my water. I get cold water sometimes....then after a while it starts getting hot...then steaming hottt. Even if the cold water is full blast. ive told them every 4 months but they keep telling me that they will fix it. Never do. I got 2 small kids and i have to wait bout an hour or so sometimes for the bath water to get cold enough to take them a bath. I have to take quick showers sometimes(3 Minutes) because if i don't the water will become so unbearably hot. Can someone inform me of the Texas Laws if any that will help me. I would like to know before i go and speak my mind to them fools at the office one last time. Thank you. Pasadena, Texas