This is a sentence from a manga (the first chapter of Slam Dunk on page 9)
["バスケット部がなんでいバスケット部が!"] seems like it translates to something like "basketball team... why the basketball team!?"...
There is a line break between the なんでい/なんだい and the repetition of the subject (バスケット部が)
...but I'm not sure why なんで is being spelled with い at the end. does that change the sentence structure as a whole to make it mean something else?