Travel Triangle — Harassment done by Travel Agent

I booked cab for 3 nights and 4 days in Karnataka through travel triangle, they demanded 15500 INR (amongst this, cash 500 was to be paid to the driver) and another travel triangle CC charge was 600, we agreed and booked the cab.
But the agent conveyed to cab manager for 2 nights and 3 days and in spite of paying the total amount, we only got cab for 2 nights and 3 days.
But on 3rd day agent asked for another 4000 INR for the last day, when we were on the way to Mysuru.
Due to that almost 1 hour wasted and we missed to visit multiple sights.
Agent Contact number - [protected]
Driver Contact number - [protected]
Hope to get proper resolution for such harassment made to the tourists by your agents when we were in a different state, that was really a bitter experience for us.