How can I fix my landlord problems?

My mom and I as well as my two brothers rent a house. The landlady lives in arizona but the house she owns is in texas. Lately we have been having plumbing issues and we ask the landlady to fix them pleading really. And she only says she will but she never does. The same goes for other house problems like broken windows, electrical problems etc. The thing is they never really gave us a contract to sign so technically we aren't really renting the house. At least not in a legal sense, i think. That's where my question comes in, is there a way to report this type of behavior even thought we aren't under any legal contract? We've been living here for 3 going on 4 years now and the only reason we don't leave is because you can't beat 850 for a four bedroom house with a backyard for pets. In fact it used to be 750 but she raised the rent recently. Also can she just up and raise our rent like that? I figure she can because there's no contract but its worth asking. I really don't know why they haven't drawn up a contract, I wish they had. Any suggestions??