@mac vs @me email

Hello!

For the longest time I have been using an @me email address. It has been set as my default email and emails sent automatically default to m @me. However, within the past day all my emails are now being sent from my @mac address and my recipients cannot reply to that email. At first I thought I had to verify it, as it was showing that it was not verified, but you can only verify it with a code sent to that email address, which I’m not getting said emails. I tried deleting it from my iCloud account and my emails still keep defaulting to the @mac address. Does anyone know how to fix this?