Union Bank Of India — Registered Mobile Number Still Not updated with my new number

Address:

New Delhi, Delhi, 110049

My name is Ajal Puri Rana.I opened my union bank account from Delhi.Currently I am working in bangalore.I lost my registered mobile number so I requested the branch in bangalore to update it with my new number.The bangalore branch told me that they can not do it from here and that the updation of my registered mobile number with my new number can be done through my delhi branch only.
So, I called my main delhi main branch.On calling my main brainch, they told me to take a form from the bangalore branch regarding the change of my mobile number, attach my id proof along with it and send it through courier to my delhi main branch address.As told by my delhi main branch, I sent a courier to them but still no action has been taken by them till now.On calling my delhi main branch today regarding my query, the staff of the delhi branch talked to me in a very rude way.So I request the union bank senior advisors to take some action regarding my query.
My delhi branch address details is given below:
Union Bank Of India
Branch:South Extension, D-43, Nd South Extension Part I, New Delhi-110049
Phone:[protected]