For context, there is a planet that is kept isolated from the larger civilization of star systems it should be connected with—in terms of communication. A base population is already present on the planet. On the remaining celestial bodies of this star system are a third party’s personnel, transport, etc. Warp tech is present so that the whole atmospheric re-entry and exit can be skipped, but it and other such advanced tech is only accessible by the third party.
This third party wants to keep the aforementioned planet isolated for the main purpose of extracting humans to do specific labor. I want this planet’s populous to be unaware of the larger context around them without breaking worldbuilding through said planet advancing too far, discovering the third party that limits them, etc. Is it possible for an entire planet be exploited without its inhabitants knowing it’s being exploited? Can the planet be kept both isolated and technologically stagnant enough so that this operation isn’t interrupted or ruined?
Edit: Thanks for the replies, they’ve been really helpful in figuring this out! Just want to pin down a couple more points. To do that, I’ll clarify the aforementioned “labor.” The peoples taken from this exploited planet would participate in something like the Abbasid’s “ghilman,” but adjusted to swap literal slavery for wage slavery.
Does this setup necessitate that the exploited planet’s people are (as per @L.Dutch) at “barely subsistence level?” Does that mean their society is something akin to dark ages Europe or remote regions of Africa? Given the most voted-upon answer as of writing this, I’m thinking of making the planet largely dependent on primary economic activity, with little secondary, and fewer tertiary activity. Would this best suit the exploitation system described in my original question, or is there a higher threshold of development that would allow the system to function at maximum effectiveness?