Harrsment by police inspector

Sir i m in defence posted in delhi .home town in lucknow.there was a girl who used to be my friend. Family relations were good .but in course of time situation get worse. That girl was in possesstion of my debit card i have given her when his dad met with an accident. Also she was carrying photos of together when we went to vaishno devi.girl went there without persual of her family. When she called me when she reached surprised but some how i managed.that photograph consisists of normal travelling photos. Even i got married with some other girl.i invited her family.her father and his little bro. Attendend the marriage ceremony.but as the six month time pass that girl along with his family and one inspector start backmailing saying that u have used girl in context of promising for marriange with my girl showing that debit card and photograph. Around 4 years of my marriage has been passed. Now the girl also got marrien wirh sime other guys .even now her parents black mailing us .and one inspector used to visit our house regularly and demanded money.how can i deal with this situation .and how i proceed further plz tell me the way.plz