I have several credit cards I no longer use, but I’ve never had one of them send me a credit decrease notice. One thing you can do is call the credit card company for more details. I bet they’d likely increase your credit again if you asked.
@terry.bryant This happened to me several years ago with a Bank of America card. I called them and basically told them what you said in your post. They agreed to give me the original limit back right away. Granted, this was probably 2017-ish. Sometimes credit card companies slash limits when they’re worried about an economic downturn, so it may not be quite as easy to get your limits restored now. But it’s certainly worth a phone call if you haven’t made one already.