Speakers not working right

I had Circuit City to install my speaker's. I have been having problems with the sound fading in/out on the front speaker's from the time Circuit City had installed them. Recently, I purchased a new radio because I thought maybe it was the radio itself. A week ago, I had the front door speaker's rewired. At this point, I have to turn the volume up louder in order to hear any sound from the front speaker's. As far as the back speaker's they have sound, but the back seem to get loud and fade a little. What advise can you give me?

Also, I have tweeter speaker's on the panel up front and the rear end. I'm sure those aren't working.