My Gf Cab Driver is missbehaving and how to fix this

My girlfriend lives in gurugram and everyday she have to take a cab. She once get a call from random guy saying ''Maam mereko aap bahot pasand ho aapse milna hai mereko'' and he said ''mereko pata hai aap kaha pr rehti ho and told the correct address of my girlfriend'' . We were skeptical that it would be a cab driver so i called that number next day and made a fake story that we need cab service and whats your name and what you do. We got to know his name and confirmation that he was a cab driver We didnt complain because we were scared that he knows the adress and if we complain that it will come to his ego and he can do anything so we thought lets ignore and block that number. Yesterday my girlfriend again got the call from the same number and this time he was very vulgur he said ''Maam mereko aapki Chu\*t chatni hai , Tera career mere haatho me hai , samne se dekhegi toh pehchan jaayegi'' upPlease help Should i do police complaint or Complaint on office. If anyone gone through similar situation help