I contacted the H.R. Dept. of my company, and they sent me a form to complete that requested a refund of my HSA contributions that I had made during the Medicare retroactive period. In turn, they sent me a check refunding those contributions. It is important that you do that before you file your 2020 taxes, which I have not done yet. Also, note that I believe you need to estimate and report your income generated by those contributions on your tax return. I believe Turbo Tax guides you through that. Since I have not filed my taxes yet, I am not 100% sure on that.
