What do I do to fit in with them?

My sisters get along and they always gang up on me. They never involve me in things and I dont know what to do. Im 3 years older then my little sister and 3 years younger then my older one. Yepp that puts me in the middle. You would think that I get along easily with both but its totally the opposite. My younger sister Malaya gets along with me only when Marley isnt around. We are like best friends and then, as soon and Marley comes in im invisible. Malaya will start making fun of me or make me off as a bad person saying, “Hmm the dog needs a bath, the owner must not care!” And then Marley will be like yeah give your dog a bath because thats going to make our dogs dirty. My dog had a bath…yesterday. They just make things up. Malayas dog peed and crapped on the floor but she was at a friends house so I cleaned up the pee, and Marley told me I had to clean up the poop. I did and I threw it away in a closed baggy. I put paper towels over the spots with specail soap and water to soak it up. She yelled at me and told me to put dog cleaner on it. There was none, we were all out. Marleys boyfriend Ray told me that we did have some so I asked him where it was and he just said never mind. Real helpful ik! Marley told me to get soap in a bowl, and scrub the floor. So I got a bowl and she yelled at me and told me I had the wrong one. I got the right one and filled it with water and soap and scrubbed the floor. After I put the bowl in the sink and she screamed at me and told me to throw it away. Then Ray told me I had to take out the garbage. It was 10 something at night, but I did it anyway. I came in and she told me to cover up the spots with towels so I put 2 hand towels down. she got mad and told me I was suppose to use paper towels. I feel like Cinderella, what the heck do I do?