Question: how to know my data balance in idea postpaid?
Answer: Log in to Self-care on www.ideacellular.com and click on 'My Plan & Services' to know about your plan, as well as a recommended plan based on your usage. ... 
Dial *121*4# or 121 from your Postpaid number.
Dial Idea customer care at 12345 from your Idea Postpaid number.