Indian Overseas Bank — mobile number registration

Address:

626101

I tried to change my mobile number linked with my account. They gave me a form and i filled it and i got all sms alerts to that number. But when i try to register for internet banking it shows mobile number is not registered with cns. I have gone to bank many times regarding this query but they are not providing any value information. So i need to know what i should do to get registered for internet banking. And also i am not able to link my bank account in any upi supporting applications. So kindly look into that too.