I literally haven't been to the doctor in four years, because the last time I went in for an X-ray they charged me immediately, and then later sent a bill for s

I literally haven't been to the doctor in four years, because the last time I went in for an X-ray they charged me immediately, and then later sent a bill for some more charges on the same X-ray. My insurance and medical provider are the same entity, which I thought was supposed to avoid this exact situation. Now I just avoid any medical treatment unless it is completely unavoidable, because I have absolutely no trust that the costs won't just be suddenly upgraded afterwords.