Padda, I think Jean is right about applying late and that may be where the large sum is coming from. If you apply late or let your coverage lapse (as I did one time) they stick you with a higher rate. The monthly premium you were quoted was based on if you had applied on time. At least that's how I understand it. Then again, this is the government and they can't get anything right, so maybe they just messed up. Good luck getting it figured out!
When it come to hemodialysis, Medicare is a bargain.