Is there a demonic ghost at my house?

I noticed there was a ghost in my house for the past 2 months (my house is about 30 or less years old) I didn't really care at first but now it seems to try and harm me and my sister. My sister and I were sitting on the couch in our living room last week and we heard a voice of an adult man coming from my basement shouting "Owen, go" and then "Caroline get away" we both heard it clear, but it was kinda quiet. It couldn't have been my parents because my mom was upstairs and my dad was in the kitchen one room away. 3 days later we heard our parents talking in the kitchen my dad mentioned that he heard knocking on the walls, but my mom didn't beleive him. Today when both of my parents were still at work my sister and I sat in the kitchen she sat in the seat by the window and I sat in front of the pantry. We were both talking about the man in the basement and then someone/something took an avacodo from the fruit basket and threw it at the back of my head with force. My sister was about to go investigate the pantry and she stepped on what looked like a tack which wasn't there before. My mom is also pregnant and we're afraid that it might harm her. What do we do and please no bad comments?