You would be able to evict the other person, yes, but you are going to have to follow the same procedure as if he was an non-paying tenant, unfortunately. That would mean an application at the Magistrates Court where the property is situated for an eviction order under the Prevention of Illegal Eviction from Unlawful Occupation Act.
This is, unfortunately, not an easy order to do yourself without at least the assistance of an attorney, even if he/she is not going to represent you. So, unfortunately, I would have to recommend that you make use of the services of an attorney to bring the application on your behalf.
It also takes about 4 - 6 weeks to get, assuming that the illegal occupant is not going to oppose the application.
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