Why is there no audio recorded with my videos?

Why is there no audio recorded with my videos?

I have owned this Camera for almost 6 years and i have dropped it once by accident, years ago but i got it fixed since it could not turn on. It was fine after repair but recently, i started vlogging and there's no audio recorded(my hard work of all vlogging go down the drain. Is there any way i can repair it without buying a new one? I'm still a student and i can't afford a new one yet.