Can my landlord leave a bathroom unusable?

Montgomery County, MD.

I'm currently in a dispute with my landlord about numerous things. But without going into detail, I've paid rent on time every month and throughout my tenancy, she's broken sooo many lease terms (like showing our home to potential buyers without telling us and before the home can even be put up for sale, according to our lease). Now, she's trying to get back at us by saying that our bathtub drainage issue is because of our dogs' hair when in fact, our maintenance man has already told her that it's from years of backup inside cast iron pipes. During this time while we're disputing, she doesn't want the maintenance man coming out to our single family home to repair the main floor tub. For over a week, the pipes have been left open, so we aren't allowed to run the water in the bathroom. She says "there's nothing wrong with the basement shower, just use that one." Obviously, this is an inconvenience. I would just like to know what my rights and options are for going about dealing with the situation. Must she repair the bathroom if we have another one in the house? How long can she take to repair it? Thanks for your help!