HDFC Bank — change of mobile number

Have a SB Account in HDFC Bank in Mylapore Branch Chennai. Now I have temporarilly come to USA for 6 months. Now I am not able to log in to my Account since after entering my Customer ID and Password, it is sending an OTP to my Indian Tel No registered (which I cannot access in USA) to go into my Account Details Page.
Now with this new procedure, I am not able to log in to my SB Account at all.

I have HDFC Credit Card to which I need to make payments before 25th Jan but cannot transfer since I am not able to log in to y Account.

I requested my Brother in Chennai to meet the Manager in HDFC Bank in Chennai with my letter ( scan copy) to effect AUTO-PAY from my A/c to Credit Card but that is also not accepted.

Bank Manager says that either they pay up/transfer from their Account to pay my credit card or else I have to submit a Form duly filled with chane in Mobile Number duly signed along with my Identity Proof attested in Physical Format to HDFC to effect Mobile Number Change so that I can receive OTP in my USA Local Tel No to log into my A/c and do all Transactions.

Now Suuport @hdfcbank.com have sent me a form for effecting change in Mobile Number but hat form is not accepted by Chennai Manager HDFC and says another Form is there which he will mail me to my registered mail ID in HDFC Records which I need to fill, sign and courier with Identity Zerox Document self-attested for the to do the change.

I think HDFC is harrassing its Customers a little too much without understanding the real problem of long distance/time change zone/genuine rerquest.

Please resolve this immediately