Wow...I had a weird bug. So i played for about a year as a paid subscriber about a year ago, and then quit a year. I wanted to start a new character, (I have only one Fed) but it said that would cost 600 zen to buy two new slots. So i *just* grinded enough dilithium to get 600 zen. About a week ago i started a klingon character, but it seemed too boring so I never got her past the tutorial. I was just about to spend my zen when i decided to delete my klingon, and loe and behold I suddenly had a slot open to get a fed. I logged out and logged back in to see what would happen, and my slot disapeered, and again it said i need 600 zen. So i quickly created another klingon character and then deleted her and suddenly i had a slot again, so this time i took it and now i have two fed characters.
And still have my 600 zen. Weird.