There should be a way for you to send your system in for repairs. Nintendo's gotta have support for your area if they're selling the 3DS there.
I had this problem once, and I never dropped or damaged it. Nintendo fixed it free of charge though.
Yup, it's a touchscreen problem. Sensors over here are responding somewhere else. By that, I mean the BF chat click is activating the TPC. The problem is probably the bottom "half" of the 3DS. Maybe try calling someone in your family to fix it? They might have to take it apart. Don't worry, I saw another thread like this. Someone dropped a computer and they took it apart and fixed it. Guessed what? It worked.