ICICI Bank — updating the mobile number

Address:

Pune, Maharashtra, 412308

I have been an icici customer since 2007; recently i moved to usa for a short assignment, my registered mobile number got deactivated and has been assigned to someone else, without knowing which i tried making transactions - otp being sent to the same number. Since this is a sensitive thing, i have tried reaching out to icici customer care several times, to get help in updating my mobile number in vain; they are not at all supportive, advising me to visit branch or atm - right now i do not have access to atm/any branch to go in person and reset the mobile number; this is highly disappointing and alarming, as my otp had been received by some stranger as these guys are not helping me out to update the mobile number. Also, ever since i know my number is assigned to someone else, i am not able to due any kind of transactions.