You could try logging in an Alt, that usually forces any other Character to be logged out, as you used to be able to use this method of disconnecting to glitch your Alts on to your main Characters friends list until they patched it not too long ago.

Maybe create if possible, a New character on the same World as you d/c from if its not set to Congested, it will have to force the other to be logged out, I have used this method to recover from d/c in an instance before, as you simply can't login two character on the same World since it was patched, it was a handy trick to add your Alts to friends list.

Worth a try if you can.

But anyway, this needs attention as mentioned above, you simply shouldn't be able to buy a name change unless the system checks the selected character is on the Home World, as required.