I must first stress, using O boards and automatic writing without proper knowledge is not a great idea. Even myself having good knowledge on hauntings and spirits, I still will not pick them up. You never know whom your going to get, they can lie to get to you.
Trying to get rid of it can be done in some different ways. First i would not use those O boards and automatic writing again, without full knowledge on how to protect yourself. You may first want to try speaking to them directly outloud and letting them know they are no longer welcome there and they need to move on. This may take many attempts but its the best chance you have. Other methods include a priest can come and bless your home. or your simple prayer may work. also placing religious symbols can help as well. Hope this helped you and good luck.

Castle of HauntsCoastal Spirit Chasers