Cannot get my @mac.com emails. Please help!

If you have an @mac.com address you also have @me.com and @icloud.com versions of the same address. Are these working? If so and the @mac.com version isn't, does it still not work on the iCloud website? Did you continue to subscribe to MobileMe up to the point where it went free, and then migrate to iCloud before July 2012? Has the @mac.com version of the address worked at any time since then?