Air India — charged business class fare but seat provided in economy class

Address:

New Delhi, Delhi

I booked 03 business class ticket (Pnr-yf8y0) ticket number[protected],[protected] and[protected]Sector delhi-bhopal) for travel date 16/02/2019 by paying 72360 miles+ rs2613.
I was issued boarding pass of business class but i when i reached inside the flight, i was shocked to see that there was no business class in the flight. All the seat were of economy class.
This was a case of cheating by air india with me.
I had to suffer mentally also because i had to travel by economy class.
Kindly take up the matter with air india