1) 왜요, 내가 티켓팔이라서? = Why, because I'm a ticket seller?
* -팔이 is a suffix meaning a (street) peddler of something, as in "성냥팔이 소녀" ("The Match (Seller) Girl"). Here it seems to mean she is used as some marketing ploy, i.e. a ticket seller in an indirect sense.
2) 그렇게 모진 소리(를) 듣고, 응, 어떻게 와? = How could you come, you know, after hearing such a harsh word?
* 모진 소리 = harsh thing to say. 모질다(a) = harsh, heartless, unfeeling.
3) 다시 무대에서 연주할 수 있다는 생각에 너무 들떠서 아무것도 못 봤던 것 같아요. = I was so excited at the prospect of playing onstage again that I did not see what I should have heeded.
* 들뜨다 = be excited (about something good). 들뜨다 + -아/어서 -> 들떠서 = because I was excited.