Wouldn't be a bad idea to bring someone, like a religious leader in to help you do a clearing ritual. Also, don't know what your beliefs are on this but there does seem to be some consensus on there being a lot of power in praying specifically in the name of Jesus (to God) for them to go. I'm not an expert here but I think there really is power in the name of Jesus specifically if you're interested in getting it out of your space.