Audio Production for Radio using Simian as playback

I record audio production for radio. I send the MP3 files
To the station using e mail. When I hear the production on the air the voice sounds out of phase. Wishy Washy sound. It sounds fine in my home recording studio. My settings are
24 bit
Medium Quality
No dither
Sample BEST

what is going on ? It is driving me

Real radio, or Internet radio?

Do they say they need MP3 format?
Do they specify:

  • mono/stereo
  • bit rate
  • Peak level
  • RMS level