Indian Overseas Bank — fraudulent transactions from stolen iob debit card in spite of email notification confirmation from the bank regarding blockade

After my IOB debit card was stolen, I made multiple attempts to reach the customer care and emergency numbers, after which they registered the complaint and also asked me to email. I emailed and after 2 hours 45 minutes got a confirmation email from the bank saying that the card has been blocked. After updating my passbook, I got to know that the card was still being used for more than 4 days and 50000 rupees had been deducted at different stores. As again, nobody at IOB customer care picks the phone. I’m highly disappointed and saddened as this is my hard earned money and IOB has been immensely careless.