Do I reduce the pay of this caregiver or not????

7 years ago I started a caregiver at a rather high rate. I need the caregiver and she was efficient. She is now age 74 and has asthma and some acid problems in her stomach. She does not hear as well either. My Mother is getting on in years and need different servies now. The caregiver told me today that if I reduce her wages and take in a seond person to help out that she will leave the job....just say the word and I am gone she told me. I fee l kind of controlled by this woman..I want to reduce her pay by one day a week and train a back-up person bec if the current lady gets ill , I have no one to help out. She tells me I can hire her daughter. I don't want her daughter!!!! or I can hire her friend!!! I don't want her friend. I find the caregiver is good and is controlling and taking on her own people for chores in my Mother's house. I want to take back my control and the caregiver tells me I will not find anyone as good as her since she has been with me for 7 years now. What do I do