I had a ghost in my house but its gone now and i want it back?

Ok im 17 my brothers 14 and we live only with our mom. Ok we had a spirit..or mabey demon... Ok so this is what used to happen My mother used to be a very negitive person and we went through a phase of tso years where she was always drained of energy she always sick and she always had health problems.. like hospital problems. at the same time she started feeling like this me and my mom both sepretly starting seeing things like i saw 3 times a black figure solid black out of the corner of my eye dash past me several times. my TV has had the volume on mute and when i went out of my room the volume would turn up to like 30 when 20 is loud... my mom saw words in like mid air, my brother used to have his things fallen onto the floor when he would be at school. and there was a **** load of negitive engery always in the house. Also to back this up we moved out a year ago and let our cousin and her new husband rent the house and the husband AND my cousin sepretly saw and experienced diffrent things and ontop of that we never told them about anything that went on when we lived there so somthing was definetly here but now its gone... And every since it was gone everything went back to normal my mom got unsick shes never sick now or tierd no wierd stuff or shadow figure has come around everything stopped... but i want to know is it lying dormant? waiting to come back? i feel its more of a demon type then a human spirit because juste verything that went on points to a demon like pressence or whatever. So will this stuff every come back?