A Dum Dum Park resident on Sunday received a text message with a number, asking him to call the Paytm customer care as his account would be blocked.

He got worried, called the number, followed the instructions of the person on the other end and downloaded an app on his phone and lost more than Rs 12 lakh within 30 minutes.

“I was barely awake in the afternoon when I received the text message…. I got a little scared and immediately called the number mentioned in the message,” the man, an official of a central government agency, said.

“The person on the phone asked me to download an app. The moment I had downloaded the app, he asked me to make a transaction of just Rs10 through Net banking. I had no clue that he would start accessing my account, once I had logged in.”

In his complaint with Lake Town police station, the man has said he hadn’t received any one-time password to validate the transaction from his bank account that is linked to his Paytm account.

After some time when he checked his bank statement, he found Rs12,12,082 had been debited from the account in four transactions, he has said.

“I was crestfallen when I found that after I had made a transaction of Rs10, more than Rs12 lakh had been debited from my account. I have reported the matter to Lake Town police station,” he said.

Preliminary investigation has suggested the person on the phone had linked another e-wallet account with the complainant’s Paytm account and transferred the sum to multiple e-wallets and web portals.

The modus operandi was a little different from the regular frauds where callers pose as bank officials and ask people to share OTPs generated on their phones to transfer money from their accounts, an officer of Lake Town police station said.

“In this case, instead of depending on OTPs, the accused linked his bank account with that of the man’s Paytm account to gain access to the man’s bank account. Once the two accounts are linked as a payment partner, there is no need to validate any transaction with an OTP,” the officer said.

On Monday evening, the man said he was still to get any redressal.

Hundreds of bank frauds — the majority of which are made through fake calls — are reported across the city every month. The number of such complaints has gone up during the pandemic when several people are at home and doing various online transactions such as paying bills or buying products, according to police records.

Many who had never tried online payments have been forced to go online, at times falling prey to online frauds or phishing mails.