You should immediately file an FIR in your nearest police station, if you are getting constant threats under section 506 and 441 of Indian Penal Code.
506 of Indian Penal Code states that whoever commits, the offence of criminal intimidation shall be punished with imprisonment of either description for a term which may extend to two years, or with fine, or with both.
441 of Indian Penal Code states criminal trespass.—Whoever enters into or upon property in the possession of another with intent to commit an offence or to intimidate, insult or annoy any person in possession of such property, or having lawfully entered into or upon such property, unlawfully remains there with intent thereby to intimidate, insult or annoy any such person, or with intent to commit an offence, is said to commit criminal trespass.
The screenshots of threatening whatsapp messages and photographs of trespassing in your house and destroying your plants can be used as strong evidence.
If police refuse to register the FIR or do not take action on registered FIR then you can send your complaint in writing to the Superintendent of Police (SP) by registered post.
GOPAL VERMA
ADVOCATE ON RECORD
SUPREME COURT OF INDIA