Yesterday I got an email notice from SSA that my statement was available so I looked at it. I was shocked to see that I was enrolled in Part B at a cost of $560 per month. I have never knowlingly enrolled in Part B and have no idea how this happened. One guess: We recently spoke to SSA (after holding for 3 hours) about adding my wife to my account. The representative may have pushed a wrong button.
I searched Medicare.gov but could not find any way to dis-enroll online (there is none).
So I did this Yahoo search: can I decline Part B medicare?
And got this answer:
How do I disenroll from Medicare Part B?
You can disenroll from Part A or Part B if you or your spouse go back to work past 65. If the employer has over 20 employees, and you are on their group health plan, you can delay Medicare. You can contact Social Security to disenroll and you need to fill out a CMS-1763 form
Fortunately I posted here about my problem and got responses that sent me back to do further investigation. It now seems that I can disenroll by filling out their form and calling SSA.
I want to thank the expats that were quick, and polite with their helpful responses. Those that were quick and impolite should check their medications.