The MC pharmacy is no longer covered by insurance.

Go to Medicare.gov and research the plans. There is a widget there that lets you enter your mom's medications and then tells you how each plan who be covered for Advantage Plans. The open enrollment period is almost here so the timing is good. It is possible that the coverage ends at the end of this calendar year and that is why they are notifying you now, right before open season.

Should hsve no problem. Ask what one they recommend.