Yes, people have the right to form groups for the purpose of achieving mutual ends (such as self-defense), but no such group has the right to require membership in the group (or payment of the membership fee), because no individual member has any such right. And no such group can rightfully claim any sort of ownership rights over a "national territory," especially when the claim includes property not owned by any voluntary member of the group. The group and its members have the right to deny you the right to enter or be on any property they presently own, but no such right can exist regarding other property--such as property you currently own.
Therefore, the country you live in has no right to evict you from your own property for refusal to pay the group membership fee. The fact that the group in question calls itself a sovereign nation (or a trust) makes no difference whatsoever.