Fraud nokia care

I am having Nokia Lumia 820 and i was having issue of display. They repaired that but instead of that the basic use of phone is to talk and they have created problem with the ear piece. I m not able to listen anything on handset and not able to listen songs. And they are telling that we have not done anything. I have spent 11000 only for repairing display. They repaired that but instead of that they have created so many issues with my phone. I am a Student i can’t spend so much money and i can’t buy new phone. That phone was very useful for me.