My a string doesnt sit in its place like it should. The piece that holds the strings and helps them resonate when played open doesnt hold my a string. I had to tilt my tuner key foward to make it sit right but it doesnt play open right? Any ideas why this happened or how to fix it? I thought it could be the strings because there pretty old( i was going to get some today but got my license instead

). Please give me any advise you have.
Thanks