The audio is not working on a samsung galaxy grand prime sm-g531f

i just received this phone, the guy who sold me said that it was perfectly working except from the front buttons on the screen, and there was another defect: the phone was little bended.

i changed the touchscreen and i fixed the frame (so the phone is not bended anymore)

but i found another problem, there is no audio, no audio from the jack, no audio from the front speaker, no audio from the back speaker but the microphone is working

i tried a reset but nothing, i tried an hard reset, but still nothing

i'm thinking that probably the banding caused some damage on the ic audio, but unfortunatley i can't identify it.

someone could help me?

where is it?which is the model?

thanks

anyone?