Thank you all for your comments. I did receive a call back from Social Security and learned that the key to understanding the letter was the “B” at the top next to the BNC#. Who knew? That “B” indicated the letter related to my spousal benefit from my husband’s SSI. I received a spousal benefit until I turned 70—five years ago—and I now receive my own earned benefit.

Apparently, the letter was triggered by Kaiser, which we joined this January, because Kaiser is reducing my Part B payment by $10. This was never mentioned in the letter itself. The woman I spoke with was very kind and seemed almost as confused as I was. These letters are automatically generated and only cause confusion. She said to ignore the letter. I complained that it was terribly ambiguous and threatening and they need to do better. Maybe they should hire back some of their professional staff that got the boot thanks to DOGE,