Private-sector lender HDFC Bank has launched its toll-free banking service which will help customers in carrying out six basic banking transactions just by dialling the numbers.Customers will receive an instant SMS with the information requested including mini statement and balance enquiry on their registered mobile number, said Nitin Chugh, HDFC Bank head (digital banking).Besides, other four services requests -- download mobile banking app, cheque book request, account statement and email statement -- can be made by dialling toll-free numbers.