Well, since the GCD is imposed server-side, that's clearly an entirely bogus reason.

Of course, and as discussed at length on these forums, using accounts with different names is a surefire way to get yourself banned, but that's not what was said on this occasion.

Keep us up-to-date with your efforts to get this fixed - it's clearly a GM screw-up, although it would be interesting to find out what put them onto you in the first place.

Purely out of curiosity, was this on the EU or US servers?