Union Bank Of India — my late father joint account is not properly transferred

Address: Lucknow, Uttar Pradesh

Sir we have a accnt [protected] in joint accnt of my father and my mother sufia sultana since 25 years in amethi branch district lucknow.
My father died on 14 july 2015 so we shifted to lucknow and requested bank to shift our account to aminabad branch lucknow
But instead of transfering as a joint account they transfer only my father s name
Due to which my mother is facing a lot of problem. She is not able to take any money.. Pension
We are facing a lot of problem