Blue Cross Blue Shield of NM review: BCBS Centennial Medicare

My sister was diagnosed with COPD about 15 years ago, and now lung cancer that has spread to her liver in June 2022. Since then, BCBS has not given her the service, nor the medications she has been prescribed for her illnesses. They either deny it completely, or only approve half of a medication that requires another kind of medication to make it work. She has one medication her Dr gives her from the samples because the insurance will not approve the medication. The insurance changes her medications at times. I thought only a Dr can change patients medications? BCBS has denied a recent PET scan they needed to find out whether her intense pain and numbness was cancer related or muscle so they could know how to treat it. Not to mention today 10.26.22. The insurance did not approve her chemo therapy until the time she was to be there. All of this is unexceptable. she is supposed to be stressless during this time. Clearly the insurance companys Drs aren't prevy to this, nor do they care. I would like to speak with the Drs that make these medical decisions about patients they know nothing about, much less their ailments.