Rejection of my transfer request

I am currently working in Bank of Baroda as an IT specialist officer. I am only child of my parents and they reside in outskirts of Kolkata. Both of them are facing immense health issues and need me to be with them as there is no one to look after them except me. I am posted in Mumbai. I have applied for transfer to Kolkata on medical and humanitarian grounds on Nov,2017. I requested designated officers again and again through letters,applications and voice calls but they did not listen to my plea and rejected my request every time saying there is no vacancy for IT officer in kolkata. I told that I am ready to work in any dept and can shift to generalist from specialist category if possible. But they continued passing the parcel to each other and I did not get any result. Department of Financial Services under the Finance Ministry has advised public sector banks to adopt ‘Preferential Transfer Policy’ for the women employees. According to the latest circular of Department of Financial Services, all the public sector banks have been advised to frame a women-specific transfer policy. The new transfer policy aims at facilitating speedy transfers for female employees, enabling them to stay with their families. For Married Female Employees: The PSU Banks should make necessary provisions as far as possible, to place/transfer married female employees at the same place or the place nearest to where her husband is stationed. For Unmarried Female Employees: The PSU Banks should make necessary provisions as far as possible, to place/transfer unmarried female employees at the same place or the place nearest to where her parents are stationed. Then why still my plea is unresolved? What action can I take in this matter?