First of all calm down. You are getting agitated over something which is not there. Police is just trying to take advantage of your agitation and fear. So taking a deep breath and calming down will be a first step.
Tell the police to go to hell. They cannot file a case against somebody who is not married to a woman. Sec.498A under which the CAW cell operates is clear that it only covers husband and husband’s relatives.
Send complaint letters to the local IG of police and every one below him right down to DCP. One to the Human Rights Commission. This generally has a salutary effect on the lower rung of police.
If that does not work, file a Sec.156-3 application in court against the said policemen and your ex-finance and her parents. Sec 156-3 is an appeal to the court to ask the police to register a case against somebody. Make out a case for harassment and intimidation. I am sure a lawyer will be able to add many more sections to it.
Please remember that 13 months is a long time. If the police had the power to register a case against you, they would have done so by now.