New Primary Domain still points to old domain

This account has been active for a while, and they are going through a rebrand. domainA is the domain that this account has had for a long time, but domainB is going to be the new domain. DNS has been set to point to the server and allowed plenty of time to propogate. I went in via WHM to modify the account and changed the primary domain to be domainB. I then added domainA as an addon domain. However, domainB still automatically redirects to domainA. I have now completely removed domainA, checked the dns and anything else I can find. domainA still works and domainB still redirects to it! What the heck is going on? I have also rebooted apache and DNS, no change. On top of that, they can't access Wordpress as wp-admin.php has a permanent direct that points to /cgi-sys/suspendedpage.cgi which I can't delete. haha I'm so confused!