They cancelled my Iowa Medicaid when I turned 65 and started Medicare. I think it depends on the state how they do that. I couldn't afford my bills after they started taking out, but finally found a part time job. I think what they said about Medicaid paying the premiums for part B is right but I think it depends on your income and I don't know what your state guidelines are.

googled it for Mississippi

Qualifications: Individuals must be blind or disabled or age 65 or older. SSI recipients are automatically eligible for Medicaid.