Your account is indeed showing as flagged for premium, so it went through and is active. May be something cached. Try going to internet explorer (even if you use firefox, etc) and dump all of your browser cookies and temporary internet files, then try logging in at both everquest.allakhazam.com and zam.com, so you get both possible login cookies. Then return to whatever browser you normally use and see if things work correctly.
If that doesn't work, let us know!