Bank failed to renew my fixed deposit

You have posted that:

"I have an Fixed Deposit in ICICI Bank which I set for auto renewal,before 2 years."

If the bank  has asked for auto renewal instructions then what for it was?

"When I requested for credit of interest with auto renewal,they refused outrightly."

Did you record it?

"Do I know how should I take it forward to get my FD with correct interest."

Submit a written representation under proepr acknowledgment to local BM, with a copy to MD/CEO and ask to accept deficiency in writing and apologise , provide relief and interest, and compensation, within next say 3 days or lodge complaint with RBI-CEPD,DCDRF.

Agitate preferably under expert advise of your counsel specializing in consumer matters.

All banks are mandated to auto renew FDs on expiry but at the current rate of interest.  If the rate of interest is lower now, you will get lower rate of interest, not the earlier one.