internet theft

My neighbor steals my wifi password with an app from google play. this is several times a day and if  i dont use the wifi they yell obscenities through the wall, Ive also caught them changing names of the devices on the xfinity app but if i pause them they change them back and then im blocked .How or where do i report them . I also think theyre unsing emulated space to watch my tv and pc. please help.