Indian Overseas Bank — suspicious transaction on my account

Hello sir/madam,
my name is sabari venkatesh. I am an existing customer of iob from peters road, chennai branch.

I received a transaction sms from iob on 12-apr-2018 at 8:12 am amounting to rs. 3432.60 which was not initiated by me. I suspect this as a fraudulent transaction.

I don't know whom to contact as some of the numbers listed on the iob website aren't reachable.

Please find the details of the transaction below:
Transaction narration: ecom-paypal rocker1030 [protected] sg-v35
Date: 12-apr-2018

i will be highly thankful if someone could guide me on how to report this and proceed further.

Thank you in advance.