Mentally disturbing by sending messages and facebook post about me

One of my school mate, become my friend during my collage day whenever i use to come home town he use to come and meet, soon i get irritated by his behaviour (drinking a lot, drinking while driving, and made too much blunder about things ) so asked him to stop talking me and calling me. and after that he disappear for a months (4-6), However i don't live in same city so he couldn't try to meet me also. And after 4-6 month he suddenly called me and talk to me where i have finally ask him to cut the call, and in few days he again called me but i ignored. And i got pissed of bcz of all these thing one day i got a call 11PM that day i was already pissed off with some other issue i tried to convince him don't call me. but he called me with one of our common friend's no. I thought my be some emergency i asked my roommate to picked-up call if its not urgent tell them i am sleeping. And few days later i got to know he is telling other ppl that i am boozing , smoking in my current city and showing my roommate's picture to all people that she is my girlfriend, i ignored again but he send me msg that i will tell ur father that you are drinking , smoking in ur current city... finally i couldn't control that day i sent him a message where i use "tu pagl h dimag ka ilaaz krwa" which he really needs.and asked him only to block me and i also blocked him from everywhre, Now he is after one month, he is telling people I made his girl fiend to breakup with him i am sure he doesn't have gf, posting on fb "xyx pagal hai block kro ise mai 5 rs dunga 10 rs dunga". He went to my father also he also ignored me as he is aware of lot of things. when he dint get any response form my father he sent messages to my company's CEO That he "wants serious action by me" I am not sure what should i do.. if police complain it might be problem for me in future. if i don't do any thing he can do worst thing.