USA, Called Asking for my Medicare Card Number

Just got a phone call. They said they had been trying to reach me several times. They said they were « closing my old account » and opening a new account number for me. I asked why I hadn’t received any letters from them. He mumbled something that I didn’t really catch and asked me to give him my medical account number. I asked why he didn’t have that information and I thought this was a scam. The dude hung up on me. I called my state insurance 1,-800 number and they verified my account was good until 2026 and they weren’t closing or opening anything. I warned the dude someone had just tried to scam my Medicare number.