Okay, I'm starting to understand better what is the meaning of MassHealth CarePlus. It is the expanded Medicaid that Massachusetts created, in response to ObamaCare, to cover low income adults who are under age 65. Unless those adults are disabled, they would not be eligible for Medicare.

During the first 2 years that you received SSDI, you were not eligible, yet, for Medicare, but you may have been eligible for MassHealth. So you could have gotten MassHealth CarePlus without being enrolled in Medicare Part B.

Once you became eligible for Medicare Part B, your MassHealth coverage is forbidden by law to pay any costs that would have covered by Medicare part B, if you had had it. All doctor bills will be your responsibility. I was unable to find a link to support this. There are plenty of links saying a person over age 65 must get Part B, if they want any help from Medicaid on doctor bills. The truth is that disabled people on SSDI, or SSI, who are under age 65, are held to the same expectation.