How do you work with a client who doesn't want your help?

Hi, I was hoping to get some advice from those who have experienced this. I am pretty new to the job (a year under my belt now) as a PCA. I have had two clients who yell at me and put me down. One of which refused to let me do my job (cleaning them after they had a messy BM in their pants). This person also stated flat out that they don't like me. I am very respectful and kind and do my job as well as I can but I don't want to invade the space of a client who doesn't want my help. Also it's very stressful being treated badly. I could use some advice. I have talked with my supervisor who just sent me back to the same client. Any suggestions? I'm in school planning on furthering my career to upgrade to an RN position eventually but situations like this make me wonder if I am choosing the right career.