Hello @patelincho
One thing I know about people like that is that they are sick inside and they will always want to get to you. The only thing is report to the Authorities and if they person cannot be caught totally ignore his/her messages.
Replying will only make them happy, use the golden rule and they will probably leave you alone.
Silence.
So far i did this and didnt help ..... I try ignore this people , i make sure there is as less ways to contakt me direct but is not helping . When this people cannot treat you direct they start contact every person to whom you ever say hello online . They ask side people to get side and they harsah your autoritet with posting lies online . This is something i cannot ignore any longer ....