I didn’t really know what to put as a title so I’m going to try and put as much detail in as I can. Basically 19 months ago my fiancé and babies dad committed suicide when my son was 20 months old. Ever since then his family and friends have blamed me for his death 
his parents have harassed me, wrote horrible things online and there had been no communication for over a year. They know where I live but because the harassment and online bullying got so bad the police gave them a warning not to contact me or come to my house. However today I’ve revived a letter from a mediation centre saying that they want to try mediation and then go on to court to see my son. I don’t know much about grandparents rights or what happens in a family court.. my son hasn’t been involved with them for over a year now and to him they are strangers... I know for a fact that if they were granted access they would try and tell my son all kinds of lies to turn him against me. What can I do? Do they have rights to him?