Same, and I just purchased new slots tonight. Seems like the store is down at the moment.
PenanceжTriage
I've got the same problem on Virtue -- 2 slots that were available are now locked...
Running City of Heroes Panel - Dragon*Con 2012 MMORPG track
I just deleted a little-used character and noticed the same thing. Slots are still unavailable.
I wanted to reserve a name for GR 
I had 3 slots dissappear on me and a few others i know on Triumph Server already /bugged it in game.
DEV's? can we PLease have our slots back ( Holds 1 Chocolate Chip cookie on end of fishing pole just out of reach. yes i know thats Evil im a Villian hehehe )
Talos Maltalomar lvl 50 Rad/Rad Corrupter - Triumph Server
Arack BloodThrall lvl 50 BS/SR Scrapper - Triumph Server
Rose's Kiss Lvl 50 Mind/Nrg/Ice PermaDom - Triumph Server
Basically, those slots are simply temporarily unavailable. I've seen this happen a fair bit to 'extra' slots (those gotten through purchases and vet rewards, I think?). If it says the store's down, then some other things will be down as well, and those slots're one of them.
The global servers are all down, again. The Store, our extra slots, In-game market, Architect, EMAILS AND ATTACHMENTS (Many, many expletives deleted).
The plastic tips at the end of shoelaces are called aglets. Their true purpose is sinister.
--The Question, JLU
Don't use email for storage and people will minimize their losses when the feature crashes, which it has done numerous times since it was put into the game just a few months ago.
Just logged onto my account, logged into Freedom, and all my open character slots are now locked? Was fine earlier and other servers appear fine but right now I am missing 6 slots.
Anyone else have this issue?