Air India — airline cancellation

I live in australia and visited india recently and i had a flight booked to go from a delhi to mumbai on 2nd nov, flight no ai665 at 8 am and pnr no z52j2. I tried to check in online and kept getting error message. Rang customer support and she told me that my flight has been cancelled and she can put me on another flight at 4 am or 8 pm same day. It took the representative 1.15 hrs to change my flight and later on i found out that my flight was not actually cancelled and it did go at scheduled time. My whole night was wasted as i had to leave home at 1 am to be at the airport in time to catch the 4 am flight. I asked several people at the airport about who i speak to and no one could direct me to the right person. I was going to mumbai for 2 days and as a result of air india incompetence, one of these days was wasted due to lack of sleep on the night.
What i want to know is :
1. Why i was not informed we if the flight was cancelled.
2. Why i was given wrong information that flight was cancelled even though it wasn’t.
3. Why customer support lied to me and wasted my 1.15 hrs and i had to pay a huge bill as i was using my australian mobile to call them.