Please let me know if I'm doing it wrong or not.
I need to exclude smartphones, windows phones and blackberry. I just need wap feature phones
These are the only brands i've chosen atm, what do you think ? Would you suggest a totally different traffic source instead ?

mainly symbian isnt it?
you're right i forgot to include it
this is the updated setup

From your screenshot I think by selecting others you might also get non - smartphone traffic.
The best way would be to ask your rep 
Also i think Nokia has a bunch of smartphones..
Definitely ask your rep/support.
Probably I'm not spending enough with Sitescout yet in order to get a proper answer..
"With our mobile targeting capabilities, you can certainly target any feature phones your desire. However, if you require information on which devices fall specifically under the "feature phone" umbrella, we'd like to suggest perusing Google or Bing to see which OS/brand(s) you should target in particular"
nevermind, I'll find out by myself