Rematching

So I am au pair (20) and I have been staying with this hf for 6 months now and I am not happy. It started off great but slowly over time it became exhausting. I worked for 11-12 hours for 3 weeks straight I never complained. The kids love me they constantly ask me to stay longer but I don’t know. So if a few months back I had to pay for the kids stuff bc their cards won’t work and I just asked for a reimbursement and suddenly they asked if I could pay half for the phone they got me. I said sure but I felt weird. For the last 2 months I have been visiting my bf some weekends. So a few days ago I had a sit down to talk about me not feeling comfortable with working overtime and they said that it’s kinda hard to manage that since they both have work. But after that they ask if I can start paying toll ( for the first time ever) I said yeah. But it seems that every time I ask for something they have to get something in return. I personally believe that they want me to stay on weekends because before I started going out I was helping around on the weekends: cleaning and taking the kids to activities. And now my car that the mom use to go to work in the city is on its last thread and could break any minute. Which leaves me at home ( I drove the car just last night and it is fine) . I have been considering rematching but what if I am with another family that is even worse or I am further away from my bf and friends here. I don’t want to risk it. I have considered just leaving the program???