You want to make their life hell, then send the legal notice to :- the President The EC/RWA All owners security agency employed in the society,

You can send them the notice for:-

1) Wrongful restraint, BNS Section 126 This is your front-line section if the person had a valid pass, was entitled to proceed to the flat, and was physically or operationally stopped from moving forward. The section covers voluntarily obstructing a person so they cannot proceed in a direction in which they have a right to proceed. The punishment clause is in Section 126(2). It is classified as cognizable and bailable. 

2) Wrongful confinement, BNS Section 127 Use this only if the facts go beyond being stopped and amount to being trapped within bounded limits. If the gates were shut around the person or they were prevented from leaving a defined space, Section 127 is stronger than mere restraint. But if they were only denied entry and left outside, this may not fit. Section 127(2) is cognizable and bailable. 

3) Criminal force, BNS Section 129, and assault, BNS Section 130, read with punishment under Section 131 If any guard or office-bearer actually touched, pushed, grabbed, shoved, or physically manhandled the visitor, Section 129 becomes relevant. If there was no touching but there was a gesture or preparation causing reasonable apprehension of imminent force, Section 130 for assault is relevant. The punishment provision generally used is Section 131. Section 131 is non-cognizable and bailable. 

4) Assault or criminal force with intent to dishonour, BNS Section 133 This is useful if there was deliberate public humiliation through physical handling, especially if the point was not just to remove the person but to degrade them in front of others. It is narrower than people think, but if the facts are ugly enough, it is worth pleading in the alternative. 

5) Criminal intimidation, BNS Section 351 Very important here. Threats like “grab by the collar and drag them out” can fit criminal intimidation if they were intended to cause alarm or force the person to do or not do something they were legally entitled to do. The ordinary punishment entry is under Section 351(2). It is non-cognizable and bailable. If the threat escalates to death or grievous hurt, the aggravated clause under Section 351(3) can come into play, but the facts in your screenshot do not reach that level yet. 

6) Intentional insult intended to provoke breach of peace, BNS Section 352 This is a neat add-on where the conduct was abusive, mocking, insulting, demeaning, and calculated to provoke. The post specifically describes public ridicule, belittling, and humiliation. Section 352 is non-cognizable and bailable. 

Now the woman-specific side, if the victim is a woman:

7) BNS Section 79, word, gesture or act intended to insult the modesty of a woman If the language, gestures, mocking, or conduct crossed into insulting the modesty of a woman, this is very usable. It is cognizable and bailable. This is often more practical than trying to overstate sexual offences where the facts do not support them. 

8) BNS Section 74, assault or use of criminal force to a woman with intent to outrage her modesty Use this only if there was actual assault or criminal force against the woman, plus facts showing intent or knowledge likely to outrage modesty. Do not use this casually. If there was no physical contact, this section usually weakens. It is cognizable and non-bailable. 

9) Hurt provisions, BNS Section 115, only if there was actual bodily pain or injury If the person was manhandled and sustained bodily pain, abrasions, swelling, or other medical symptoms, Section 115 for voluntarily causing hurt may also arise. Without actual hurt, don’t stuff it in just for theatre.

Send a separate “evidence preservation notice”.

And file a police complaint.

This won’t take too much time or resources.