Pension Claim - Ranbaxy was acquired by Sun Pharma and his pension documents have not been cleared

Hello Senior's, My father worked in Ranbaxy Pvt. Ltd. company for 40 years and got retired 3 years back ie 2016. Ranbaxy was acquired by Sun Pharma and his pension documents have not been cleared.
I live in a different city and would like to help my father however from where I should start I have no clarity. Ranbaxy Pvt. Ltd registered office was in Delhi and later shifted to Gurgaon, Haryana and Sun Pharma registered office is in Baroda, Gujarat.
My father visited Pension office in Dwarka, Delhi however he said the details shows some other employees or wrong details in the records. He constantly in touch with Sun Pharma office in Baroda and the HR department mentions that they have sent the correction to Dwarka, Delhi office thrice in past 6 months however the pension office says his details are still the same and they have no notification from Sun Phrama.
I am being in a different city unable to understand whom to call or if any thing can be done online.
I would really appreciate if anyone can help me with some information in this regard. I hope I am not confusing, if any other details are needed please do let me know.

Get a copy of the communication from sunpharma and submit the same to dwarka, it may be in misc receipt and not filed appropriately

Thanks alot Sharma ji, Do you think an email copy will suffice, which I can print out and take to Dwarka office or tell my father to take it.
Best,
D