For dispute resolution regarding banking transactions for an individual there are courts and ombudsman.My suggestion, don't let it go. File an FIR, these scams happen a lot nowadays, so one should be double sure about all these thing
Never trust a stranger, even though they might sound legit.
Paytm is useless when comes to dispute, I also had similar problem in the past, and they will simply raise their hand and ask us to settle (buyer and seller). If they had a similar dispute mechanism like American express, Paytm would've grown much bigger.
Don't give up
Any organisation if it thinks that it might loose face will act quickly so it does not depend on bank to bank or economic body but it depends on the severity of the case.
That's why I am telling don't loose patience and let the legal machinary take its time for your dispute to be solved.