I can pretty much assure you that no accounts have been deleted from the server.
Gamespy does this from time to time. I have six gamespy accounts for this reason. Also, some time ago they gave priority for nicknames to subscribing customers, so at any time a paying customer may take your nickname, thus disabling your account.
I suggest creating a gamespy account using a nickname that no subscriber would ever want. The two that have worked best for me over the last while are StinkyDonutHole and wexert. Pick something equally unsavoury or improbable or unidentifiable and you should be OK.
Thankfully subscribers accounts are probably too expensive to allow this to be used to squeeze opponents out of tournaments or gamespy API multiplayer servers, however if you were rich and vindictive enough you could buy out just about any gamespy API multiplayer server.