"Uh, Hi -I was just calling to say you're giving me too fast of internet"
"What?"
"Yeah I'm being reamed 29.99 for your LGE SUPER FAST 500KB internet, and I seem to be getting 2mb - its just too fast"
". . ."
"Could you please apply less kukuru butter to my backside next time? Thanks!"
Those X's is what happens when you downgrade, you can't access them till you upgrade your account subscription again. Still going with the, they're on different servers option :P (jk, but it seems like you got a nice bug lol).
If it continues to lock characters I believe the one that won't lock is the first one in your list. So I hope the first character in your list is your main.