My friend is refusing to pay back the money he owes me. What can I do to get it back?

Under Indian law, your mobile provider’s actions are likely unfair and exploitative. You can file a complaint with the Telecom Regulatory Authority of India (TRAI) and the consumer forum. You have the right to seek a refund of the unauthorized charges, and switching to prepaid or porting your number does not necessarily relieve you of these unfair charges.