I have the early 2011 MBP 13" and just recently when i plug in headphones, music doesn't come out of the left headphone. i've tried about 5 different headphones and its all like that. I bought apple care when i purchased the laptop

so i have just under 2 years left (got it october 2011).
what do you think they can do for me? i booked an appointment for sunday with the GENIUSES