The TK Jakarta ticket office is normally efficient, competent and they respond quickly also to emails ([email protected] or [email protected]; +62 21 5795 7666 from 9 am to 6 pm) while I try I avoid the global customer service line at all costs. I mean this supposed you bought your ticket directly with TK website or app otherwise you have to contact your travel agent. Do not just rely on the information from TK website as it is notoriously buggy and erratic as happens after a short flight reschedule of few minutes you may not be able to do anything to your booking.