My Xfinity package was changed without my authorization. I was grandfathered in the best premium package.

My Xfinity package was changed without my authorization. I was grandfathered in the best premium package. No for approximately 15 dollars a month less I have slow internet and no premium channels. I have complained to Comcast but still waiting for a call back.i have been customer for 40 plus years and am a senior citizen. I would never agree to this new plan. Help ?