There are HUGE differences between selling Land and selling an Area!!!!
Selling Land transfers full ownership of ALL chunks within that Land. Selling an Area makes the buyer a permanent "tenant" of the area. When selling an area, the buyer becomes the Owner of the area and a Member of the Land. They do not own the Land or the chunk.
Once the Area is sold, the Land owner can no longer unclaim the chunk. The owner also cannot kick the tenant out.
Think of this like a permanent rental. The renter has rights but they will never expires because they "bought" the area instead of "renting."
✍️ Renter can give up their claim to the Area command
Stand in the area and then type:
/land rent cancel
This removes the person from the area. The owner is back to full control.