When you are on Medicare you have to review your RX and health insurance providers at the end of each year for the next year. Last November 2012 I logged into the Medicare site, entered my RX drugs then reviewed the suggested providers.
CIGNA claimed they covered more of my RXs than any other. I chose them as the most cost effective provider. In January of 2013 they changed their formulary and removed coverage of one of the most expensive drugs.
We are required to stay with our provider but they are not required to honor their commitment to you. I will NEVER subscribe to CIGNA again.
Monetary Loss: $1200.