Bank Of India — delay / unable to change my mobile number

Address:

Pune, Maharashtra, 411003

Hello sir,
I am a account holder of bank of india, khadki branch, pune. Pin - 411003
This complaint is in regards with the contact number which i intended to change and it's been many days they haven't acted on this. I had gone to the bank and filled the form. The lady managar says that she is the alone woman handling so this will take a long time. Is this the way the bank handles its customers? I will never prefer such govt. Banks henceforth.
Request you to please check on this.