My Earbuds Won't Work.

Hello, I was wondering what is happening to my earphones. My chord pulled out of the part that plugs in and I put it back together with some electric tape and it helped. I was walking to school this morning while listening to music and they were working fine. When I was in my first period class, I tried listening to my music and I found out that my left earphone doesn't work. I was wondering if it was the pulled chord and if it is, what I could do to get my earpone back to working.