Try a soft reset and if that does not work then try a hard reset. Also try to clean the jack input and see if that fix the problem and if not then your in the same boat as me. I'm using a bluetooth for audio stuff.
Thank you for your post and welcome to the Nokia forum.
Please visit a local Nokia Care Point where your phone can get checked and repaired. Depending on the cause of the damage this will be covered under your warranty, the Care Point will be able to give you more information about this. Make sure to bring proof of purchase with you.