Why does my iphone 4 have no audio during calls?

I do admit, I dropped my phone the other day and now i have this problem. Just wondering if it's an easy problem to fix?

I can make a call, but i hear no ringing and when the person picks up i hear absolutely nothing and they can't hear me. I tried putting them on speaker when I spoke to the person but still silence.
Strange thing is, I can still play music and recorded my voice. Also, someone left me a voicemail and i could hear that perfectly.
So why is the problem just when i make calls? It can't be a problem with the mic or speakers?

:D strange.show it to technician da

You broke it when you dropped it.