How do I get my landlord to fix something or return my deposit?

Put your request in writing and keep a copy. Say what is wrong, when it started, and what you are asking for, with a reasonable deadline. Take dated photos. For a deposit, many states set a deadline for the landlord to return it or list deductions, so look up your state's rule. If you get no answer, your local housing office or small claims court may be the next step.