I've never used the BitFoG service, but I'm inclined to say "it's gone forever." The problem is that whatever address you sent the bitcoins to is in possession of those coins. If it's a tumbler service then I assume whatever address you said you want it ultimately sent to will end up in possession of those coins. If you "deleted" the information for that address via BitFoG or any other service... there's no way to recover it unless you somehow regain access to that bitcoin address.Hopefully that generic info is enough of an answer for you.