Union Bank Of India — service related issues

Address:

Darjeeling, West Bengal, 734004

I have an savings account with union bank. I need to update my mobile number in my account. Right now i am out of station. I called to the customer care they suggested that just give a call to home branch for that purpose and also i got your branch contact details from them. I have tried several number of times but nobody response to me on[protected].
Then i have tried another number i. E;[protected], one person picked up the call and told me this is a std telephone booth number, never called back and also he talked with me very rudely. I am surprised that what kind of service you have? Everytime physically present at branch is not possible. I got transferred to the another city. I have already sent mail to branch manager and regional head. But i didn't get any revert from them. Actually these people are talking this matter very casually.
So, it's request, that how to change this contact details please assist me and take a action against this people for harassment bank customers.

Yours faithfully,
Debadrita dutta
My home branch ifsc code :ubin0550213