This is the case in South Africa as well. You can't simply evict a squatter or a non-paying tenant. You have to go the legal route. They can continue to occupy your space for 90 days until the court gives them notice. You also cannot claim damages from them.
I had a similar scenario few years ago, with a tenant that was not paying for 5 months. I couldn't evict them, so I started removing stuff from the apartment gradually to make it uninhabitable (doors, window panes, cut off water, electricity, etc), which eventually forced the tenant to leave

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