Unitech Group — not allowing authorized person to visit my flat

Address:

Kolkata, West Bengal

I have purchased a flat at Fresco Tower, New Town, Kolkata. The Flat was handed over to me in 2018. Presently I am in USA. So it is not possible to visit my flat frequently. For any emergency and for looking after the flat i have authorized my nephew. On my request when he wanted to visit the flat 2 week back, the facility centre personnel of Kolkata did not allow him although it was very urgent as some contract work was going on in side the flat. They informed that each time owner has to send e-mail about the visit. This system is totally impractical and bogus. The name and contact number of my nephew was in the emergency contact person list. In spite of that they did not allow him. Even they are not ready to tell what is the procedure to authorize my nephew to visit my flat.
As per my opinion, security should check a valid photo id proof of owner or authorized person or person enlisted at the emergency contact list and if found ok, they should allow him/her.
The responsible person of the facility centre is not also answering any of my email and totally careless. Kindly any one help me what to do or whom should i contact to resolve this problem. My contact e-mail id is [protected]@gmail.com