Hi Paul,
I totally hear your frustration! You should be proud that you even got them to grow from seed! [thats quite the accomplishment!] I take it that these have not bloomed for you? and of course, understandeble that you dont want to freeze to put them in a blooming condition. I don't really know what to suggest about the cold treatment,and unless you just keep them as foliage plants, you are probably doing all you can.

paul, I'm sure it's frustrating not having a choice of temperatures in your apartment. Do you have any outdoor space (balcony, outdoor windowsill, fire escape) where you could put them in the fall for a while?

Why don't you try to swap them for something else more suitable for your growing conditions, rather than pitching them. I'm sure someone would be happy to take them off your hands. (I've already got one that I'm waiting somewhat impatiently to bloom, so I don't need any more!)

hang in there Paul. Don't give up.... they're worth it.