Can I File a Case Against My Uncle and Parents

Hi,
I am a software engineer (24 yrs old).I want to marry my boy friend.We both tried convincing our respective parents.
His parents were very happy about this relation. My parents also agreed initially.But, behind my back they started calling my boy friend's parents and threatened them(like forced them not to say yes for this marrriage infront of me, if they say yes then will spoil his sister's career, etc).Later point of time i got to know that my uncle(mom's cousin brother) also involved in this. Till now threatening is happened only on phone calls. But I fear they shouldn't do anything to his family/himself.

My uncle is a politician.He can do anything with their family. I am scared about this....Please anyone help me to come out of it.
Is there any law in constitution, that I can file a case on my uncle and my parents for this.

I am not sure why it matters what either family thinks. Assuming that your boyfriend is a legal adult, then you can just get married.

If your uncle is making threats, then the people receiving the threats can speak to the police as to whether or not these might rise to the level of criminal acts.

Unless your boyfriend is a minor, as long as you both choose to do so and you are not prohibited by familial status, just do it.